Metrics details The objective of this study was to determine the number of stages of cone drying and immersion that yield the maximum number of high quality seeds Nine variants of the process were conducted; they differed in terms of dwell time in the drying chamber and water immersion time Each extraction variant consisted of five drying steps (lasting 10 Each drying step was followed by cone shaking in a purpose-made laboratory drum The process variants were evaluated and compared in terms of cone moisture content as well as the dynamics of seed yield and the quality of seeds obtained in the various steps The studied process of seed extraction can be described using the Lewis empirical model for the second stage of drying with the b coefficient ranging from 0.34 to 0.60 Relatively higher initial and final moisture content was found for cones immersed for 15 min (more than 0.45 kgwater·kgd.w.−1) while the lowest moisture content was found for those immersed for 5 min (less than 0.4 kgwater·kgd.w.−1) The highest seed yield at the first and second steps was obtained in the 8 h_10 min variant (53% and 32% the mean cone yield amounted to 65% of total seeds in the cones; seeds obtained from all variants were classified in quality class I The procedure recommended for commercial seed extraction facilities consists of three 8 h drying steps and two 10 min immersion steps with cone shaking in a drum to maximize seed yield A shorter cone extraction process maintaining an acceptable level of seed extraction may reduce energy consumption by nearly 50% There are gaps in knowledge about the number of sequential drying and immersion steps and their duration to ensure the maximum effectiveness of the seed extraction process The time the cones spend in the dryer can take up to half the time of the entire process of seed extraction which makes drying the most energy-consuming part of the process Such procedures also cause high levels of dust in the seed extraction facility which is hazardous and requires additional precautions on the part of the operators Practitioners use two types of cone moistening: immersion (e.g. seed extractory in Lasowice Małe; Kluczbork Forest District) and spraying (e.g. seed extractory in Czarna Białostocka; Czarna Białostocka Forest District) The research problem arises from the absence of detailed information concerning the commercial extraction of seeds from larch cones or the efficiency of the thermal method (with immersion) applied for that purpose It is not known how many drying and immersion steps should be used to ensure the right drying/moisture parameters to obtain the greatest possible quantity of seeds without compromising their quality the duration of such steps should be investigated to make sure that the process is economically and energetically sound it is predicted that during the subsequent immersion step the cones will be able to absorb more water The laboratory study involved European larch cones collected from the seed orchard at the beginning of December 2019 in the Grabowiec Nursery by the Czarna Białostocka seed extraction facility Plant study was carried out in accordance with the regulations in force in the State Forests in Poland Permission was obtained from the municipality of Bielsk Podlaski to use the collected larch cones for research The national number in the register of suppliers of primary forestry material from which the cones were obtained was MP/3/41001/05 and the certificate of provenance for the cones was MR/60849/20/PL (based on the Polish Act of June 7 2001 on forest reproductive material (Journal of Laws of 2015 The collected cones were transported to the laboratory of the Department of Biosystems Engineering divided into batches and stored in an LKexv 3600 laboratory refrigerator (Liebherr Switzerland) at + 2 ± 1 °C prior to the study All cones had their height (h) and diameter (d) measured using an electronic sliding caliper (model 677,256 from Silverline Tools Great Britain) with an accuracy of ± 0.1 mm and their initial weight was determined using a WPS210S laboratory balance (Radwag The cones were divided into ten batches with 32 cones per batch; nine batches were designated for testing the extraction process and one constituted controls not subjected to any treatment The controls were placed in individual containers without drying They were kept at room temperature in open containers The seeds that were naturally released from them were collected and transferred to a germinator The nine studied seed extraction variants differed in terms of drying and immersion times Each variant of the procedure consisted of five drying steps of 10 five steps of shaking in a drum for 30 min A stage is defined as one single cycle of drying shaking and optionally immersion and soaking the cones Variants are the names of entire processes each of which begins with placing the cones in a dryer and ends with an evaluation of the quality of the seeds obtained in the process Effective extraction time was defined as the sum of all drying, immersion and shaking times during the entire procedure. In turn, total process time also included cone soaking after steps 1, 2, 3, and 4 (Fig. 1, Table 1). Scheme of the seed extraction process: (a) drying; (b) shaking in a drum; (c) immersion; (d) soaking the cones were acclimatized at room temperature (20–22 °C) for about 1 h at a relative air humidity of 40% after measuring the size and weight parameters a batch of 32 cones was placed on perforated shelves in a Heraeus UT612 convection dryer with air circulation (Kendro Laboratory Products GmbH the temperature in the dryer was 35 °C for the first 2 h and then it was increased to 50 °C until the end of the process to prevent the seeds from thermal damage the cones were removed from the dryer every 2 h to weigh them and separate the seeds that had been released individual cones were put in tightly sealed P17 geotextile bags and then placed in a drum and shaken for 30 min The drum rotated at 30 rpm and was tilted at 30° from the horizontal (patent claim no and the number and weight of the seeds were recorded the cones were immersed in plastic containers half-filled with distilled water at 24 °C (± 1 °C) for 5 the cones were taken out of the containers and placed on a cotton fabric at a controlled temperature of 22 °C for 12 and then soaking and soaking—the first stage of the process is complete During the second and subsequent drying steps the cones were weighed prior to placing them in the dryer; the rest of the procedure was exactly the same as before neither immersion nor soaking was performed (only drying and shaking of cones) The temperature and humidity in the dryer and in the laboratory were monitored with a FTH 100 m (Geo FENNEL Kassel Germany) with an accuracy of 0.01 °C and 0.01% the cones were dried at 105 °C (± 1 °C) in the dryer to constant weight Dry weight measurements made it possible to calculate the initial and final moisture content as well as determine instantaneous moisture content in the cones throughout the process where u–instantaneous cone moisture content during the extraction process \({[\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}]\) u0– initial cone moisture content in a given step \({[\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}]\) uk–final cone moisture content in a given step \({[\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}]\) b–coefficient characterizing moisture content change [h−1] the seed extraction rate was calculated from the formula below: Formulas 1 and 2 were used to describe the course of seed extraction in successive steps of the studied nine variants The dynamics of seed extraction was assessed by calculating the cumulative number and weight of the seeds released in the process using the following formula for the seed yield coefficient After the extraction process was completed the number of open scales capable of producing two seeds was analyzed as they are structural elements determining the course of seed extraction Statistical analyses were performed using the Statistica v The normal distribution of cone size and weight parameters was assessed using the Shapiro–Wilk test Differences in mean size and weight parameters were assessed by ANOVA F and Duncan’s test The homogeneity of variance was also tested using the HSD Tukey test All analyses were performed at a statistical significance level of 0.05 Cones used in all the test variants did not differ from each other in terms of height (coefficient of variance in the Student t-test–F = 1.33 at p = 0.23) Analysis of variance revealed a significant difference for cone humidity (F = 2.52 at p ˂ 0.05) diameter and initial weight are factors that can determine the course of the extraction process the relationship between diameter and height for all cones used in the study was described using a linear regression equation \((y=0.2794x+8.3195)\) which means that cone diameter increased by 0.28 mm per 1 mm of cone height The initial weight of cones may be associated with their harvest time or storage conditions A linear regression equation was also used to describe the relationship between the height and initial weight of the examined cones (y = 0.238x–3.918) which means that initial weight increased on average by 0.238 g per 1 mm of height Table 2 shows means with standard deviations the minimum and maximum values of the measured parameters the coefficient of variation and the standard error for the entire set of studied cones and seeds The Shapiro–Wilk test showed that the examined characteristics had a normal distribution The HSD Tukey test revealed one homogeneous group for cone height encompassing all variants and two homogeneous groups for diameter The first group consisted of all variants except 7 and the second group included all variants except 2 One homogeneous group was obtained for initial weight Two homogeneous groups were found for moisture content The change in cone weight in each step of the extraction process depended on its duration temperature and humidity conditions in the extraction cabinet as well as on the initial moisture content of the cones Humidity inside the drying chamber decreased to an average of 30% after 2 h of the process in each step as a result of increasing temperature the humidity inside the chamber declined significantly and then (over 2 and 4 h) it decreased further only slightly The initial moisture content of cones (u0x) in most variants increased with each extraction step due to immersion the final moisture content (ukx) was the highest in the first extraction step and decreased or remained at the same level with each subsequent step The mean initial moisture content for the three process variants with 10 h of drying was 0.411 \({\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}\) the mean moisture content decreased to 0.130 \({\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}\) The mean initial moisture content in the fifth extraction step was 0.437 \({\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}\) and the final moisture content in that step was 0.071 \({\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}\) Cones dried for 10 h reached on average 7% moisture content after extraction steps 4 and 5 The mean initial moisture content for the three process variants with 8 h of drying was 0.412 \({\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}\) the mean moisture content decreased to 0.128 \({\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}\) The mean initial moisture content in the fifth extraction step was 0.440 \({\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}\) and the final moisture content in that step was 0.064 \({\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}\) Cones dried for 8 h reached on average 7.1% moisture content after extraction step IV and 6.4% after step V The mean initial moisture content for the three process variants with 6 h of drying was 0.389 \({\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}\) the mean moisture content decreased to 0.129 \({\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}\) The mean initial moisture content in the fifth extraction step was 0.415 \({\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}\) and the final moisture content in that step was 0.084 \({\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}\) Cones dried for 6 h reached on average 8.9% moisture content after extraction step IV and 8.4% moisture content after step V which means that their final moisture content was higher than that of cones dried for 8 h and 10 h The cones with the longest immersion time (15 min) were characterized by the highest initial moisture content in each extraction step as compared to the other two variants (immersion of 5 min and 10 min) with the same drying time The final moisture content in a given extraction step differed between cones with different immersion times Cones with an immersion time of 15 min were characterized by the highest final moisture content in individual extraction steps and those with 5 min immersion revealed the lowest final moisture content The Tukey HSD test revealed homogeneous groups in terms of initial moisture content (u01, u02, u03, u04, u05) and final moisture content (uk1, uk2, uk3, uk4, uk5) in each step, as shown in Table 4 four homogeneous groups were found for the final moisture content after extraction step V (uk5): the first one consisted of all variants except for 7 the third one comprised of variants 7 and 8 while the fourth one was constituted by variant 9 alone The lowest value of the b coefficient was recorded for the first step of the 10h_15min variant (b1 = 0.34) while the highest value was obtained for the fifth step of the 8 h_15 min variant (b5 = 0.60) In the process variants involving 10 and 8 h of drying the b coefficient increased with each extraction step until the third one; in the fourth step it slightly decreased and in the fifth step it remained constant In the variants with 6 h of drying the b coefficient almost peaked in the second extraction step and remained at a similar level until the fifth step In the first steps of the variants with 6 h of drying the mean value of the b coefficient was 0.54 and did not differ significantly from the coefficients obtained during the other steps It was noted that in the 8 h_15 min variant the b coefficients increased over successive steps Figures 2–3 show examples of curves of actual and model changes in moisture content and the rate of extraction for sample cones, one each for variants 10 h_15 min and 8 h_15 min. Diagrams: (a) actual and predicted changes in cone moisture content, (b) extraction rate in five extraction steps for larch cone no. 32 in the 10 h_15 min variant throughout effective extraction. Diagrams: (a) actual and predicted changes in cone moisture content (b) extraction rate in five extraction steps for larch cone no 17 in the 8 h_15 min variant throughout effective extraction Equations for changes in moisture content and extraction rate in consecutive extraction steps are given below for the graphically for the cone shown in Fig. 2 (no Step I: \({u}_{1}=0.264\cdot {\mathrm{e }}^{\left(-0.38 \cdot {\tau }_{i}\right)}+0.107\) ,\(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.100\cdot {\mathrm{e }}^{(-0.38 \cdot {\tau }_{i})}\) Step II: \({u}_{2}=0.372\cdot {\mathrm{e }}^{\left(-0.44 \cdot {\tau }_{i}\right)}+0.095\) \(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.164\cdot {\mathrm{e }}^{(-0.44 \cdot {\tau }_{i})}\) Step III: \({u}_{3}=0.397\cdot {\mathrm{e }}^{\left(-0.49 \cdot {\tau }_{i}\right)}+0.086\) \(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.195\cdot {\mathrm{e }}^{(-0.49 \cdot {\tau }_{i})}\) Step IV: \({u}_{4}=0.536\cdot {\mathrm{e }}^{\left(-0.44 \cdot {\tau }_{i}\right)}+0.080\) \(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.236\cdot {\mathrm{e }}^{(-0.44 \cdot {\tau }_{i})}\) Step V: \({u}_{5}=0.485\cdot {\mathrm{e }}^{\left(-0.46 \cdot {\tau }_{i}\right)}+0.076\) \(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.223\cdot {\mathrm{e }}^{(-0.46 \cdot {\tau }_{i})}\) Equations for changes (Fig. 3) in moisture content and extraction rate in consecutive extraction steps are also given for this cone (no Step I: \({u}_{1}=0.304\cdot {\mathrm{e }}^{\left(-0.53 \cdot {\tau }_{i}\right)}+0.113\) ,\(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.161\cdot {\mathrm{e }}^{(-0.53 \cdot {\tau }_{i})}\) Step II: \({u}_{2}=0.292\cdot {\mathrm{e }}^{\left(-0.55 \cdot {\tau }_{i}\right)}+0.085\) \(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.161\cdot {\mathrm{e }}^{(-0.55 \cdot {\tau }_{i})}\) Step III: \({u}_{3}=0.369\cdot {\mathrm{e }}^{\left(-0.70 \cdot {\tau }_{i}\right)}+0.077\) \(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.258\cdot {\mathrm{e }}^{(-0.70 \cdot {\tau }_{i})}\) Step IV: \({u}_{4}=0.379\cdot {\mathrm{e }}^{\left(-0.71 \cdot {\tau }_{i}\right)}+0.059\) \(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.269\cdot {\mathrm{e }}^{(-0.71 \cdot {\tau }_{i})}\) Step V: \({u}_{5}=0.428\cdot {\mathrm{e }}^{\left(-0.77 \cdot {\tau }_{i}\right)}+0.060\) \(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.330\cdot {\mathrm{e }}^{(-0.77 \cdot {\tau }_{i})}\) equations for changes in moisture content and extraction rate in consecutive extraction steps are given for cone no Step I: \({u}_{1}=0.308\cdot {\mathrm{e }}^{\left(-0.58 \cdot {\tau }_{i}\right)}+0.0904\) ,\(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.179\cdot {\mathrm{e }}^{(-0.58 \cdot {\tau }_{i})}\) Step II: \({u}_{2}=0.346\cdot {\mathrm{e }}^{\left(-0.63 \cdot {\tau }_{i}\right)}+0.1070\) \(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.218\cdot {\mathrm{e }}^{(-0.63 \cdot {\tau }_{i})}\) Step III: \({u}_{3}=0.368\cdot {\mathrm{e }}^{\left(-0.63 \cdot {\tau }_{i}\right)}+0.0837\) \(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.232\cdot {\mathrm{e }}^{(-0.63 \cdot {\tau }_{i})}\) Step IV: \({u}_{4}=0.387\cdot {\mathrm{e }}^{\left(-0.68 \cdot {\tau }_{i}\right)}+0.0838\) \(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.263\cdot {\mathrm{e }}^{(-0.68 \cdot {\tau }_{i})}\) Step V: \({u}_{5}=0.396\cdot {\mathrm{e }}^{\left(-0.65 \cdot {\tau }_{i}\right)}+0.0743\) \(\frac{d{u}_{1}}{d{\tau }_{1}}=-0.257\cdot {\mathrm{e }}^{(-0.65 \cdot {\tau }_{i})}\) with a slight deviation in the first three extraction steps and with a very good fit in the fourth and fifth steps The lowest fit was found for the cone subjected to 6 h drying which may be caused by insufficient drying time (the cone was exposed to 35 °C for 2 h Table 2 presents data on the number of scales and seeds for the studied cones There were from 33 to 70 open scales per cone From 1 to 76 seeds were extracted per cone The weight of the extracted seeds ranged from 0.001 g to 0.651 g On average, 70% of the seeds were extracted from cones used in all nine study variants, with 30% of the seeds remaining in the cones. Table 7 shows the number of seeds extracted in individual variants and the number of seeds remaining in the cones The greatest number of seeds was obtained in process variants 2–73% The lowest seed yield was obtained from variant 4 (65%) In all study variants, some of the seeds were obtained in the process of extraction in the chamber and some in the process of shaking in the drum (Table 7) The highest number of seeds in the chamber was obtained in variant 2 (69%) the largest quantity of seeds was obtained in the chamber in the 10 h variants and the lowest quantity in the 6 h variants Comparing different process variants of the same drying duration the greatest number of seeds in the chamber were obtained in variants 2 and 7 (and also in variant 8—only 1% fewer) The greatest quantity of seeds extracted by shaking in the drum was obtained in variant 9 (44%) 38% of seeds extracted in all variants were obtained by shaking in the drum It can be seen that in each of the variants and their individual steps, the highest number of seeds was obtained after 6 h of the process. Figure 4a–c shows the percentage of seeds obtained during the effective extraction time, where the number of seeds extracted at a given step was added cumulatively to those from the previous steps. Percentage seed yield dynamics for each step of a five-step extraction process: (a) 10 h of drying As regards the 8 h process (Fig. 4b) on average 30% of all extracted seeds were obtained in the in the first extraction step in the 8 h_5 min and 8 h_15 min variants and as much as 53% in the 8 h_10 min variant An average of 27% of all seeds were extracted in the second step The 8 h_10 min variant was characterized by the highest seed yield beginning in the first step of the process (as compared to the 8 h_5 min and 8 h_15 min variants) As far as the variant with 6 h of drying is concerned (Fig. 4c) 46% of all extracted seeds were obtained in the first step scale deflection and the number of obtained seeds are not assessed during the process as is the case with pine and spruce cones due to the difficulties caused by the aforementioned morphology of larch cones (Tyszkiewicz The presented diagrams show that a satisfactory seed yield (60%) was obtained in variants with 8 and 6 h of drying already after 10 h of effective extraction time The seed yield coefficient, α (3), and the cone mass yield coefficient, β (4), for each extraction variant are presented in Table 8 The seed yield coefficient was the highest for variants 2 (0.73) and 3 (0.72) and the lowest for variants 4 (0.65) and 6 and 9 (0.67) The cone mass yield coefficient was the highest for variant 5 Table 9 presents germination energy (E) and capacity (Z) for the control seeds as well as for seeds obtained from the various steps of the nine process variants as well as their corresponding quality classes This is also corroborated by the fact that the highest germination energy and capacity was revealed by seeds from variants with 6 h of drying while the lowest germination indicators characterized seeds from the 10 h variants seeds from variant 1 exhibited the lowest germination energy and capacity and seeds from variant 8–the highest who noted that under the same temperature and humidity conditions the quality of seeds from cones with a lower moisture content did not deteriorate in contrast to the quality of seeds obtained from cones with a higher moisture content The germination capacity of seeds calculated from the mean capacity of seeds obtained from the same extraction steps of all process variants was similar at 45% for each of the steps in the study the authors investigated a five-step process of extracting seeds from larch cones involving immersion and heat treatment to maximize seed yield It was found that the two-step process widely used in extractories is insufficient while a four-step process does not lead to a significantly higher number of obtained seeds a three-step process appears to be optimal Each successive extraction step resulted in seeds with lower mean germination energy but germination capacity remained at a similar level in all steps which means that the obtained seeds belonged in quality class I An analysis of the value of European larch seeds should be based on their origin and the costs of extraction energy attention should be given to the provenance of larch cones and their genetic (e.g. if the seeds are extracted for the purpose of long-term storage the right extraction conditions are critical to avoid compromising seed quality due to excessive drying and immersion time the economic rationale of seed extraction should be considered given the high energy costs to address the question whether it would be possible to use a shorter drying time (6 h) with immersion (5 min) and a minimum of 30 min of shaking after each step which was shown to result in a seed yield of 71% in the present study The power rating of the laboratory dryer used in this study was 2.2 kW which means that energy consumption per drying step was 22 energy consumption in a five-step process was 110 It should be noted that the difference between the longest and the shortest drying time was significant Energy consumption for an extraction process involving three drying steps of 8 h each would be 52.8 kWh which is twice as low as for a process with five drying steps of 10 h each A comparison of nine variants of five-step seed extraction revealed the highest yield for the 10 h_10 min variant (73%) the highest mean yields were obtained for the 8 h_10 min variant (53% and 32% while in the third step the highest yield was found for the 10 h_5 min (22%) variant seed yield increased with drying duration (on average 5% for 10 h and 8 h and 4% for 6 h) The recommended process consists of three 8 h drying steps and two (rather than five) 10 min immersion steps which was greater than in the other variants The gains from subsequent extraction in the next two steps were very low (approx 11% and 5% of seeds in the fourth and fifth steps A five-step process may be conducted when the cones are derived from a valuable source and it is advisable to extract the highest possible quantity of seeds The mean germination energy and capacity did not differ significantly between the selected process variants which places the extracted seeds in quality class I Extended drying times does not significantly lead to decreased seed quality The extraction process can be described according to Lewis’s empirical model for the second drying stage the initial moisture content of cones (u01) usually increased with each successive process step due to immersion in each step cones exposed to the longest immersion time (15 min) were characterized by a much higher moisture content than the ones exposed to shorter immersion times The same was true of the final moisture content with the highest values found for cones following 15 min of immersion and the lowest for cones after 5 min of immersion The b coefficient ranged from 0.34 to 0.60; it was noted that in the 8 h_15 min variant it increased with each successive step Instantaneous cone moisture content during seed extraction \({[\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}]\) Initial cone moisture content in a given extraction step (1–5) \({[\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}]\) Final cone moisture content in a given extraction step (1–5) \({[\mathrm{kg}}_{\mathrm{water}}\cdot {\mathrm{kg}}_{\mathrm{d}.\mathrm{w}.}^{-1}]\) Coefficient characterizing moisture content change in a given step (1–5) [h–1] Critical value of the correlation coefficient Polonica (Racib.) Domin) - genetic structure of the population and its origin in the light of isoenzyme studies vegetation modelling and genetic analyses of modern tree populations to reconstruct the history of Larix in Europe Comparison of methods of seed extraction by drying cones and mechanical one of European larch seeds Larix decidua Mill Multiphase process of European larch Larix decidua Mill seed extraction: A case of Czarna Białostocka Comparative analysis of variability of morphological characteristics of European and Japanese larches with their hybrids O Taкcoнoмичecкoм Cтaтyce Лиcтвeнниц Кaмчaтки И Кypильcкиx Ocтpoвoв Ha Ocнoвe Mopфoлoгии Ceмeнныx Чeшyй Шишeк A comparative analysis of seed and cone characteristics and seed-dispersal strategies of three pines in the subsection sabinianae Recent advances in emerging techniques for non-destructive detection of seed viability: A review Direct seeding reduces the costs of tree planting for forest and savanna restoration Deterioration of orthodox seeds during ageing: Influencing factors physiological alterations and the role of reactive oxygen species Potential contribution of the seed bank in coniferous plantations to the restoration of native deciduous forest vegetation Plantlet rescue in a soil seed bank to produce forest species seedlings Multiphase process of European larch Larix decidua Mill Seed extraction: A case of Czarna Białostocka Psychrometric tables for use in pine and spruce seed extraction plants Empty seed production in European larch (Larix decidua) Seeding of forest coniferous trees and shrubs Cone and seed production from stone pine (Pinus pinea L.) stands in Central Range (Spain) Whitebark pine (Pinus albicaulis Engelm.) seed production in natural stands Assessing the influence of climate on cone production of longleaf pine forests Industrial waste heat recovery: A systematic approach Reducing energy demand: A review of issues A framework for modelling energy consumption within manufacturing systems Technology Innovation for Energy Intensive Industry in the United Kingdom Genetic aspects of wood properties of European larch (Larix decidua Mill.) Estimating the distribution and productivity characters of Larix kaempferi in response to climate change Using a trait-based approach to compare tree species sensitivity to climate change stressors in eastern Canada and inform adaptation practices Performance of softwood bark comminution technologies for determination of targeted particle size in further upcycling applications Added-value for wood bark as a coating layer for flooring tiles Options for the conversion of pulp and paper mill by-products in Western Canada New technologies and techniques in forest seed 1 (Scientific Notebook of the Forest Research Institute Dynamics of the process of seed extraction from pine cones Pinus Silvestris L Modelling convection drying of blanched parsley root slices A critical analysis of the drying curve for shelled maize Application of convection drying models to modelling of drying apples with infrared radiation Theory of convective drying of agricultural products Principles of seed evaluation in State Forests in Poland: ‘Elements of genetics and selection breeding of forest trees’ Seeds of forest and wooded trees and shrubs Current state of our knowledge about Polish larch (Larix polonica Rac.) The possibility of using neural networks to predict the size of the change in the volume of dried material during its moistening Temporal and spatial variation in scots pine resin pressure and composition Hydration-induced reversible deformation of biological materials Evaluation of force generation mechanisms in natural The structural and mechanical basis for passive-hydraulic pine cone actuation The kinematics of scale deflection in the course of multi-step seed extraction from european larch cones (Larix decidua Mill.) taking into account their cellular structure Towards unraveling the moisture-induced shape memory effect of wood: The role of interface mechanics revealed by upscaling atomistic to composite modeling Hygroscopic motions of fossil conifer cones Role of apophysis and outer scale tissue in pine cone opening [Pinus serotina On the shape transformation of cone scales 4D pine scale: biomimetic 4D printed autonomous scale and flap structures capable of multi-phase movement Fiji: An open-source platform for biological-image analysis Download references The authors express their gratitude to Mr Kazimierz Tulski for his help in the implementation of the construction of the invention—a drum for shaking seeds from cones and M.A.; formal analysis: E.T.; writing–original draft preparation: E.T.; writing–review and editing: M.A All authors have read and agreed to the published version of the manuscript The authors declare no competing interests Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations Download citation DOI: https://doi.org/10.1038/s41598-022-22942-2 Anyone you share the following link with will be able to read this content: a shareable link is not currently available for this article Sign up for the Nature Briefing: AI and Robotics newsletter — what matters in AI and robotics research CA Immo exits non-core market Serbia with the sale of the 19,600 sqm office building Sava Business 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office building in Gdańsk-Oliwa communications and security company Motorola Solutions has signed a five-year lease renewal 18,000 sqm at the Green Office complex in Kraków’s Podgórze district Falling interest rates and easing monetary policy across the eurozone and CEEi are boosting investor confidence in the region’s commercial real estate market reveals Colliers in its ‘Beyond Real Estate | Economy’ report Panattoni is to build the Panattoni Park Mainz Süd in Erbes-Büdesheim bei Alzey Axi Immo has presented its latest report “Warsaw Office Market – Q1 2025 The market opened in 2025 on a steady footing with a notable increase in leasing activity and a modest decline in vacancy landlords continue to focus on upgrading existing assets and prioritizing quality over quantity Convenience store chain Żabka has officially opened a new logistics centre in Kąty Wrocławskie The first stage of the development will serve 1,500 stores in the Wrocław area Romanian Post has leased over 5,000 sqm of logistics space in CTPark Bucharest to serve as its temporary regional courier and logistics hub for Bucharest JLL has announced the sale and leaseback of two properties by a manufacturing company in a deal worth over PLN 1 bln Warehouse developer CTP is adding 2,000 sqm to its Clubco coworking development in Brno pbb Deutsche Pfandbriefbank has extended an investment facility to PineBridge Benson Elliot for the Diuna Office Park in Warsaw The hotel market in Bucharest continued its recovery in 2024 while the ADR has finally surpassed the milestone of EUR 100 Torus has announced its All.inn students’ residence concept that is soon to appear on ul BIG Poland has acquired the Multishop Suwałki retail park comprising 13,000 sqm of retail space The company now owns nine fully commercialized retail parks in Poland Slate Asset Management has sold three OBI retail stores to the Lindner Group from Germany Cushman & Wakefield has conducted a survey the findings of which are presented in the report From Shopping to Experiences: A Customer’s View on Shopping Centres and Retail Parks Cushman & Wakefield notes that despite evolving shopping trends both retail formats continue to hold strong appeal Multi Poland has taken on the management of the Galeria Przymorze shopping centre in Gdańsk The store offers lifestyle and sporting clothing and is to open this spring According to the "Quo Vadis E-commerce" report released by Cushman & Wakefield the online commerce continues to be a growth driver for the industrial & logistics real estate sector generating significant opportunities for developers and investors the investor behind the Projekt Góraszka shopping and entertainment complex in Wiązowna on Warsaw’s eastern outskirts has obtained a building permit for a mixed-use development Poznan-based company Scallier is opening another facility under the Funshop Park brand in Romania According to the latest report “At a Glance: Modern Retail Market in Poland Q4 2024” from BNP Paribas Real Estate Poland Poland’s retail market experienced record growth in 2024 Cushman &Wakefield has summarised the situation on the Polish retail market Over half a mln sqm of new retail space came on stream last year marking the highest new supply level in Poland since 2015 This robust development activity occurred amid rising demand from new retailers and improving consumer sentiment which boosted retail sales A new retail park with a total area of 24,000 sqm is set to be developed in Otwock under the name Świderek The investment will be led by Redkom Development Empik has opened a flagship store in the revitalised former Cepelia pavilion in the centre of Warsaw the modernist building has regained its former glory and once again impresses with its original appearance and modern interior Trei Real Estate Poland has opened its 40th Vendo Park The investment was created in Wrocław and has 5,000 sqm Vendo Park Wrocław is the first facility under this banner in the capital of Lower Silesia The retail park was built on a plot of approx An 800 sqm Biedronka grocery store is to open on the ground floor of the Moje Bielany residential complex which is being developed by CeMat A/S at ul Wólczyńska 121 in Warsaw’s Bielany district Spring has very much sprung and everywhere is bathed in the first warm sunshine of the year I have in the back of my mind the terrifying fo .. The Polish warehouse market has finally stabilised after the post-pandemic boom but new challenges and opportunities are on the horizon for the sector UBM Development has been given the go-ahead for the first wooden office building in Poland: Timber Park in Poleczki Business Park in Warsaw The office market in Warsaw is currently experiencing a period of stability in terms of supply and take-up Recent data on overall tenant activity indicates that clients in the cap .. Receive all the latest information from the world of real estate by e-mail the construction of the Aura residential building designed by Robert Konieczny's office KWK Promes According to a report by research company Spectis “Construction companies in Poland 2025-2030” the total revenues of the 300 leading construction gro .. The Globalworth Foundation has provided the authorities in Bucharest with office space for a Covid vaccination centre Panattoni BTS and Commercecon together support the establishment of the second Centaurus Foundation centre in Poland to help horses and other animals intends to focus on operations in other reg .. Six class A office buildings in the PRO Portfolio which is jointly owned by PineBridge Benson Elliot and Sharow Capital have been granted BREEAM In-U .. Who won this year's 14th edition of the Eurobuild Awards The jury and guests gathered at the Double Tree by Hilton hotel in Warsaw chose this year's .. Enjoy the last set of recordings with comments straight from this year's MIPIM we asked experts from our home country for their input will take place on 9-10 April 2025 at the Norblin Factory Event Hall in W .. we invite you to hot episode of the "Eye to eye" podcast The UN Nansen Refugee Award award will go to Poland for the first time According to the office of the UNHCR High Commissioner this year's regional wi .. Czech developer CTP has been granted a EUR 200 mln loan from the European Investment Bank for the roll-out of its large-scale solar panel installation .. while the ADR has finally surpassed the milestone .. Jarosław Szanajca plans to resign from the position of president of the management board of Dom Development at the end of the year and join the superv .. The Polish and Danish governments have entered preliminary discussions for the construction of a tunnel between Szczecin and Copenhagen underneath the .. Viterra has moved into its ​​new 1,500 sqm offices in Olivia Prime part of the Olivia Centre business complex in Gdańsk Panattoni has acquired two properties near Gothenburg The brownfield sites will be replaced by a modern 43,000 sqm facility Contemporary cities are grappling with the challenge of fostering dynamic growth while alleviating environmental pressures Colliers has taken over the management of the Studio B office building located in the Warsaw Wola district The property is owned by Stena Real Estate .. The University of Warsaw has signed a contract with the general contractor for a project at ul The new building will house the faculti .. Velis Real Estate Tech is officially changing its name to Singu adopting the title of its property management product the construction of the Panattoni Park Unterfranken has officially started The PFCs show that it is possible to reach the balance between the most important objectives of the forestry forest management aimed at wood harvesting scientific studies and widely comprehended education The PFCs also prove that the sustainable multifunctional forest management counteract forest threats resulting from developing civilization New forest technologies are tested here and the Forest Service are trained The results obtained from the research conducted in PFCs are implemented in each units of the State Forests. the principles of ecological development are disseminated in forests managed by the State Forests National Forest Holding The PFCs are also a forum for cooperation between theforesters and the society Each PFC has its own scientific and social council consisting of the representatives of local authorities but also science experts and respectable members of local communities It is noteworthy that the idea of promotional forest complexes is extraordinary and indigenous promotion of ecological forestry the only cross-referential idea of model forests has been put forward in Sweden whereas outside Europe there is a similar initiative in Canada The idea of creating PFCs has been widely recognized by European foresters and scientists Total area of Promotional Forest Complexes - 1 267 803 hectares A very strong magnitude 6.5 earthquake occurred in the Norwegian Sea near Svalbard island 2025 at 3.33 am local time (Arctic/Longyearbyen GMT +1) The depth of the quake could not be determined but is assumed to be shallow.The quake was felt by many near the epicenter The shallow depth of the quake caused it to be felt more strongly near the epicenter than a deeper quake of similar magnitude would.