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1.
Fruits of Pyracantha crenulata were collected from two locations varying by approximately 550 m in elevation from south aspect for assessing seed maturation indicators. The mean seed size (length×diameter) across the collection dates varied between 1.61 ± 0.7 and 4.93 ± 0.06 mm2 across both the locations. The seed moisture content negatively correlated with germination. The change in fruit colour from dark green to light orange, the range of fruit moisture content (30.43% ± 0.06 to 36.10% ± 0.25) and the seed moisture content between 68.8% ± 0.68 and 71.6 ± 0.62 coincided with maximum germination and appear to be major indicators of seed maturation in Pyracantha crenulata.  相似文献   

2.
Forest gaps are important in forest dynamics and management; however, the gap size that is most conducive to the decomposition of litter and promotion of nutrient cycling in forests remains poorly understood. The mass loss and nutrient release from Pinus massoniana and Toona ciliata litter in response to gap size classes were determined in south-western China during a 1.5-year litter decomposition experiment. One site with a closed canopy (CK) and seven sites with forest gaps of 100, 225, 400, 625, 900, 1 225 and 1 600 m2 were established in a P. massoniana plantation in the Sichuan Basin of China; the CK site (fully shaded) was treated as the control. After 540 d, the mass and carbon (C), nitrogen (N) and phosphorus (P) contents in the litter of the control treatments decreased by 58.23%, 60.81%, 65.62% and 57.82% for P. massoniana litter and by 91.17%, 80.76%, 73.66% and 64.55% for T. ciliata litter, respectively, compared with the initial amounts. Most of the C, N and P were released from both tree species during the first 90 d of decomposition, although the temperature and moisture conditions were very low. The mass loss and C and N release rates for the two tree species and the P release rate from T. ciliata litter were higher in the 400–900 m2 gap sites than in the other gap sites and the CK site, whereas the P release rate from P. massoniana litter was greater under large and medium-sized gaps (400–1 600 m2). The mass loss and C, N and P release rates were positively correlated with the soil moisture content in the seven different gap size treatments, with the soil moisture content representing the best predictor of litter decomposition. Therefore, our results indicate that medium-sized gaps (400–900 m2) can promote decomposition by changing the environmental conditions and may accelerate nutrient cycling in forest ecosystems.  相似文献   

3.
Summary A comparison between identically sampled CAT-scan images of five wooden test pieces (Pinus sylvestris) showed that the CT-number in each pixel varied with a standard deviation of ±3.9–11.1 CT numbers. This inaccuracy in CT-numbers is called noise. As long as the direction of rotation can be controlled the noise in CAT-scan images of wood can be assumed to be approx. ±4 CT-numbers in each pixel. A calculation showed the average CT-number must differ ±1 unit to distinguish average CT-numbers in 2 × 2 × 1.5 mm volumes within solid wood. It has previously been shown that a change of ±1 CT-number corresponds approx. to a change in density of ±1 kg/m3. On the other hand, there is a difference in X-ray absorption coefficients between wood and water. Thereby dry wood densities in corresponding volumes must differ approx. ±2 kg/m3 to significantly be distinguished. The corresponding figure is approx. ±6 kg/m3 for wet wood densities with moisture content levels ranging from 6–100%.  相似文献   

4.
Sixteen quarter-sawn boards (100 × 40 mm2) of regrowth Eucalyptus regnans (Mountain Ash) were conditioned to various moisture contents to investigate the effect of mean moisture content on collapse recovery. The results support the recommendation that boards should be reconditioned at a mean moisture content of between 15 and 20%. It is likely that the actual amount of collapse recovery was nearly as good for moisture contents up to about 25%. The main disadvantage with reconditioning boards with a moisture content of between 20 and 25% was the additional normal shrinkage that occurs because of the early reduction or removal of drying stresses. The samples in this study were dried under mild conditions for long periods of time to minimise the presence of moisture gradients.  相似文献   

5.
Abstract

The present work reports on the main physical and mechanical properties of Pinus leucodermis mature wood, one of the least studied coniferous species in south-east Europe. Pinus leucodermis heartwood specimens were found to have average density values of 0.73 g cm?3 at equilibrium moisture content of 11.5% and average density of 0.64 g cm?3 under oven-dry conditions. The overall tangential shrinkage was 3.4% and the radial shrinkage was 1.9%. The modulus of rupture was on average 77 N mm?2, while the static modulus of elasticity averaged 7087 N mm?2. The hardness of P. leucodermis heartwood using the modified Janka test was 33.4 N mm?2 in the transverse direction and 48.0 N mm?2 in the longitudinal direction, while its compression strength parallel to grain was approximately 41.6 N mm?2.  相似文献   

6.
自然脱水过程中七叶树种子生理特性的变化   总被引：1，自引：0，他引：1  
喻方圆  杜艳  沈永宝 《林业研究》2006,17(2):103-106
于 2003 年研究了自然脱水过程中七叶树种子生理特性的变化。结果表明:七叶树种子对脱水高度敏感,为顽拗性种子。种子成熟采收时含水量高达 60.3%,种子在室温下自然干燥 30 天后,含水量下降到 30.2%,此时种子生活力完全丧失。在脱水初期,种子发芽率有所上升,但随后种子发芽率迅速降低。随着含水量的下降,种子浸出液相对电导率上升,但当含水量在 53.7% 到 50.9%之间时,种子浸出液相对电导率出现异常升高。同时种子超氧化物歧化酶(SOD)的活性随脱水时间的延长而下降,只有种子含水量在 53.7% 到 50.9%之间时出现例外。丙二醛(MDA)含量在脱水初期缓慢上升,在含水量下降到低于 50.9%时,丙二醛(MDA)含量快速上升。可溶性糖含量随脱水时间的延长缓慢上升。当种子含水量为 47%–60%时,种子发芽率较高,说明这一含水量区间有利于种子生活力的保持。图 6 参 13。  相似文献   

7.
The nanometer scale structure of cell walls in sugi wood (Cryptomeria japonica D. Don) and the hydration dependence were examined by the small angle X-ray scattering technique. Disk-shaped scattering patterns were observed for sugi wood. The radial average of two-dimensional data from the cross section could supply the scattering intensity with statistical accuracy much higher than that obtained from the sector average of the streak-shaped scattering pattern, and both the scattering intensities provided similar structural information. The scattering patterns from the cross section of the wood are characterized by rhombic or cross-shaped isointensity curves for the lower q region and by circularly symmetric isointensity curves for the higher q region. This shows that the disk-shaped scattering has two different kinds of scattering origins. The microfibril radii in the cell wall were determined by fitting the model scattering function of cylindrical fibrils to the scattering data. Values of 12.3 ± 0.3 and 12.2 ± 0.3 were obtained for the fibril radii of the neighboring earlywood and latewood, respectively, in dry specimens. A drastic structural change of the cell walls was detected with increasing water content from 40% to 100%. A low q rise in the scattering intensities below 0.1–1 became weak and changed into a flat pattern, and the rhombic isointensity curves changed to cross-shaped patterns in the two-dimensional scattering from the cross section. The calculated radii R increased from 12.2 ± 0.3 to 13.3 ± 0.1.Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, Japan, April 2002  相似文献   

8.
The diatomaceous earth (DE) Dryacide® was tested under laboratory conditions on surfaces (2 g DE/m2) and in wheat grain (3 kg DE/t wheat) at a relative humidity of 70±5% and a temperature of 22±1°C. The wheat had a moisture content of 14.5%. The effect of surface treatments was tested onEphestia kuehniella, Oryzaephilus surinamensis, Tenebrio molitor andTribolium castaneum. The efficacy of grain treatments was determined usingEphestia elutella, O. surinamensis, Sitophilus granarius andTribolium confusum. In both treatments adult and larval stages were included.100% mortality were reached with the surface treatments in adults and larvae ofO. surinamensis and the adults ofT. molitor andE. kuehniella after an exposition time of 3–9 days. AgainstT. castaneum and the larvae ofT. molitor andE. kuehniella no complete control could be achieved.In the grain treatments the dosage of 3 kg DE/t wheat reached 100% mortality in all tested pests exceptS. granarius. Most sensitive wereO. surinamensis andE. elutella. InT. confusum the adults died within 13 days of treatment, but for complete control of the larvae 13 weeks were necessary. AgainstS. granarius the silica dust showed no satisfactory efficacy, because 49 days after beginning of the examinations beetles of the progeny hatched. Dryacide® could not prevent the reproduction of the granary weevil, but there was a lower number of progeny compared to the untreated control.  相似文献   

9.
The very decorative heartwood of Brosimum guianense is internationally well known. Snakewood, as it is colloquially known, is represented in wood databases (e.g. the DELTA or InsideWood) as well as in lists of commercial timbers of many timber trading companies. The very decorative heartwood is hardly available and gains prices of up to 25 €/kg in form of half stems. In the present study, the chemical composition and especially the subcellular cell structure was analysed by means of UV microspectrophotometry to explain the high natural durability and some extraordinary physical properties in addition to the anatomical composition. The heartwood consists of approximately 39% lignin, 54% carbohydrates and 0.4% lipophilic compounds of unspecified origin. The fibres are very thick-walled. Numerous sclerotic tyloses and organic deposits are present in the vessel. The extractives in high content are also components of parenchyma cells as well as in tyloses, respectively. These detected phenolic extractives, partly of flavonoid character, are also part of the cell wall. Calcium oxalate crystals are deposited in the upright and square cells of rays and sporadically in axial parenchyma cells. These facts are reasons for the famous natural durability of Snakewood. The sapwood density ranges from 1.1 to 1.4 g/cm3 for heartwood (12% mc). The compression strength (119 N/mm2), the bending strength (241 N/mm2), the modulus of elasticity (23,200 N/mm2) and the hardness (196 N/mm2) indicate exceedingly high elastomechanical properties.  相似文献   

10.
In order to determine their effects on growth and mortality of instar II Hypsipyla grandella (Zeller), larvae were fed with leaf disks taken from shoots of susceptible species (Cedrela odorata L. and Swietenia macrophylla King) scions grafted onto resistant ones (Khaya senegalensis Desr. A. Juss and Toona ciliata M. Roem.), from their reciprocal grafts, and from both intact and autografted plants. In addition, crude leaf extracts from the susceptible and resistant plants, as well as from C. odorata grafted onto T. ciliata plants, were tested on C. odorata leaf disks. Mortality was evaluated 2, 10, and 25 days after starting the bioassay. Leaf area consumed and weight gain per larva were assessed 2 days after starting bioassay. Time to reach pupation, pupal weight and length 1 day after pupation, and time to adult stage and appearance of wings were determined at the end of the bioassay. Plant species significantly affected mortality (P ≤ 0.04) throughout the test. Eighty to 100% of larvae fed leaf disks from intact T. ciliata and its autograft, or C. odorata onto T. ciliata and its reciprocal graft died in the first 2 days of evaluation. All other factors measured, except pupal weight and length, were also affected (P ≤ 0.01) by the leaf disks. Intact resistant plants and reciprocal grafted plants reduced leaf consumption and caused larval weight loss. Larvae fed on K. senegalensis grafted onto S. macrophylla extended by 8 days the time to pupa and to adult stages and induced abnormal wing formation compared to larvae fed intact leaves of C. odorata. Crude extracts from resistant plants equally affected larval survival and performance compared to crude extract from C. odorata grafted onto T. ciliata plants, and these extracts were more detrimental to larvae than those from susceptible species. This study demonstrated that grafting borer-susceptible species on resistant rootstocks can affect the survival and performance of instar II H. grandella larvae.  相似文献   

11.
Effects of stratification, desiccation, radicle pruning, and season of sowing on Quercus vulcanica germination and growth were studied to identify optimum nursery procedures for artificial regeneration of this species. Following stratification (0, 2, 4 and 8 weeks), acorns were germinated, and acorn moisture content and germination performance were also determined at various times during desiccation. In early December unsprouted acorns were planted in containers, and in early April sprouted acorns, which had been stored in polyethylene bags at 4 °C, with radicles left intact or with radicles pruned back to 1.0 cm were planted in containers.Stratification for 2 and 4 weeks did not increase germination percentage but significantly increased germination rate. Germination percentage of the seeds dropped when the moisture content of the seeds was reduced by desiccation, and the critical minimum moisture content of the recalcitrant Q. vulcanica acorns was found to be 11–16%. Spring sowing of sprouted acorns altered the morphology the containerized seedlings and caused the formation of significantly more main roots, but resulted in significantly less shoot height and shoot dry weight. Spring-sown sprouted acorns had also a significant advantage over the fall-sown unsprouted acorns in seedling survival, and thus nursery personnel should not be concerned if acorns sprout before sowing.  相似文献   

12.
Seeds of Celtis australis were collected from 13 different sources, ranging from 550 to 1980 masl, in Central Himalaya, India. Significant (p = 0.05) variations were observed for seed traits among provenances. However, among various characters, seed weight exhibited maximum variation between seed populations compared to other morphological characters. Between provenances, seed weight ranged from 47.8 to 83.1 g/1000 seed, with mean value of 66.9 ± 10.7 g/1000 seed. Significant (p = 0.01) positive correlation was found between morphological characters of seeds including seed weight and elevational range of seed source. For one year old seedlings, average shoot and root growth was 61.1 ± 13.3 and 30.5 ± 5.4 cm, respectively, irrespective of provenance variation. Inter-comparing biomass yield of the seedlings with altitude, average biomass production was 8.4 ± 2.5, 9.4 ± 3.3 and 12.7 ± 1.7 g/plant, respectively, for low (550–1000 masl), middle (1050–1250 masl) and high (1350–1980 masl) altitudinal populations. Significant (p = 0.01) positive correlation between growth performance of seedlings and altitude of the seed source was recorded. Across the provenances, shoots had the highest proportion of total biomass (42.3%), followed by leaves (32.6%) and roots (24.6%). Among various provenances, Badiyargaon, Agroda, Guptakashi, Jakholi, Gajeli, Srinagar and Palampur populations produced heavier seedlings and grew faster compared to seedlings of other sources.  相似文献   

13.
In order to analyze the effect of temperature gradient on moisture movement during highly intensive drying, such as microwave-vacuum drying, the profile of the temperature and moisture content in sealed wood whose opposite faces were subjected to temperature gradient for a short time was measured. The ratio of the moisture content (MC) gradient to the temperature gradient (dM/dT) was calculated and the factors influencing moisture movement under nonisothermal conditions were discussed. The results indicate that moisture moved in wood from the warm surface to the cold one even if opposite faces of the sealed wood assembly were exposed continuously to different but constant temperatures for a short period. The moisture content on the cold surface was higher than that on the warm surface. The moisture content gradient opposite to the temperature gradient was established, and the dM/dT was below 0.9%/°C. The temperature in the sample and the distance from the hot surface of the sample was strongly linearly correlated. With an increase in temperature, initial moisture content and experimental time, the dM/dT was significantly increased. __________ Translated from Journal of Beijing Forestry University, 2005, 27(2): 96–100 [译自: 北京林业大学学报, 2005, 27(2): 96–100]  相似文献   

14.
Variation in natural susceptibility of the black alder population to Phytophthora ×alni (PA), the oomycete pathogen causing a devastating disease of alder, and its possible relationship to geographic origin, was studied in vitro using branch inoculation tests. Ninety black alder genotypes from different regions of the Czech Republic and two isolates of PA were employed. Host susceptibility varied significantly. After 1 week of infection, the lesion surface areas ranged from 254 to 2051 mm2 and from 19 to 970 mm2 for the two isolates, respectively. The differences were also dependent on the geographical origin and altitude of the sites from which particular host genotypes were taken. These findings have important implications for restoration plantings and for PA resistance breeding programmes, as there is potential to make selections from natural populations.  相似文献   

15.
 We evaluated the protective effects of floor cover against soil erosion in three types of forest located on steep slopes under a humid climate: 22- and 34-year-old Chamaecyparis obtusa (hinoki), 34-year-old Cryptomeria japonica (sugi), and 62-year-old Pinus densiflora (red pine) stands. We measured sediment transport rates (sediment mass passing through one meter of contour width per millimeter of rainfall), using sediment traps, before and after removing floor cover. Raindrop splash erosion was dominant in the experimental stands. Floor cover percentage (FCP) during the preremoval stage varied from 50% to 100% among the four stands, and sediment transport rates ranged from 0.0079 to 1.7 g m−1 mm−1. The rates increased to 1.5–5.6 g m−1 mm−1 immediately after removing floor cover, and remained high throughout the experiment. The presence of physical cover near the ground has a crucial effect on sediment transport on forested slopes. The protective effect ratio (the ratio of the sediment transport rate in a control plot to that in the removal plot) in a young hinoki stand, in which the FCP decreased markedly, was 0.3 at most, which is close to the rate for bare ground. The protective effect ratio in the red pine stand was ≤0.003. We concluded that the protective effect of floor cover in undisturbed forests in Japan differs by over two orders of magnitude, based on comparisons with previous studies. Received: March 11, 2002 / Accepted: August 16, 2002 Present address: Department of Forest Site Environment, Forestry and Forest Products Research Institute, Ibaraki 305-8687 Japan Tel. +81-298-73-3211; Fax +81-298-74-3720 e-mail: miura@affrc.go.jp Present address: Department of Forest Site Environment, Forestry and Forest Products Research Institute, Ibaraki 305-8687 Japan Tel. +81-298-73-3211; Fax +81-298-74-3720 e-mail: miura@affrc.go.jp Acknowledgments This study was supported by the Research Council of the Ministry of Agriculture, Forestry, and Fisheries, of Japan. We thank H. Ujihara, S. Ujihara, and M. Ogasawara in Otoyo, Kochi, who provided the experimental stands used in this study. We also thank K. Hirai, S. Kuramoto, E. Kodani, and the rest of the staff at the Shikoku Research Center, Forestry and Forest Products Research Institute, for their help in conducting the experiments. Correspondence to:S. Miura  相似文献   

16.
The effects of nutritional treatments and the flowering promoter Paclobutrazol™ on tree growth and fertility were studied in unpedigreed seedling seed orchards (SSOs) of Eucalyptus camaldulensis and E. tereticornis at two locations in southern India. At Pudukkottai, a semi-arid site in Tamil Nadu State, five treatments were applied: (1) untreated control, (2) nitrogen (two doses of urea at 217 g N/tree), (3) nitrogen plus phosphorus (two doses of 312 g single superphosphate), potassium (two doses of 83 g muriate of potash) and trace elements (two doses of 10 g sodium borate and 25 g zinc sulphate), (4) pollarding trees at 4 m height with application of N, P, K and trace elements, (5) drenching with the flowering promoter Paclobutrazol (0.25 ml active ingredient per cm of stem girth) along with N, P, K and trace elements. At Panampalli, a higher-rainfall site in Kerala State, only treatments 1, 2 and 3 were applied. Four replicates of treatment plots sized 18 m × 18 m, with 22–32 trees per plot were set up in each orchard in randomized complete block designs. Untreated plots of E. camaldulensis and E. tereticornis at Pudukkottai displayed 12 and 21% fertile trees, respectively, in the first year of monitoring, while at Panampally the percentage of fertile trees in untreated E. camaldulensis plots was higher at 72%, and that of E. tereticornis similar at 23%. Both species attained greater stem diameter at breast height at age 9 years at the higher-rainfall location but there was no significant impact of fertilizer application on 9-year diameter at either site. Diameter was reduced by pollarding and Paclobutrazol application at Pudukkottai. Only Paclobutrazol produced a significant increase in fertility in both species for four successive years, increasing the percentage of fertile trees to 59 and 71%, respectively, for E. camaldulensis and E. tereticornis 1 year after application. The number of capsules produced per tree also increased significantly with Paclobutrazol application, although the difference was comparatively less by the fourth year. The number of capsules per umbel did not differ significantly between locations, whereas the germination rate varied between treatments although no consistent trends were observed.  相似文献   

17.
The canopy structure and interception of photosynthetic photon flux density (PPFD) in a 10-year-old Kandelia candel (L.) Druce stand were investigated before and after artificial defoliation. Leaf and wood areas for different layers were measured through area–weight relationships of subsamples. PPFD was measured at specified heights before and after leaf clipping. The leaf area index (LAI) and wood area index (WAI) were 4.501m2m–2 and 1.412m2m–2, respectively. There was a strong linear relationship between the cumulative wood area © and leaf area (F) densities from the top down to a given depth of the canopy, C = aF (r 2 = 0.950), with a proportional constant a of 0.096 ± 0.008 (mean ± SE). The PPFD relative to that above the canopy (relative PPFD; I R) at a given depth of the canopy was assumed to be given by the equation I R = e–(KCC+KFF ) = e–KF , where the apparent light extinction coefficient K (= K F + aK C , where K F and K C are respectively the light extinction coefficient of leaves and woody organs) was calculated to be 0.502 ± 0.041 (mean ± SE) m–2m2 before leaf clipping. After leaf clipping, I RC = e–KCC is satisfied. As a result, the value of K C was estimated to be 0.785 ± 0.046 (mean ± SE) m–2m2. The light extinction coefficient of leaves K F was calculated to be 0.427m–2m2 using the indirect method, K F = K – aK C, and 0.432 ± 0.026 (mean ± SE) m–2m2 using the direct method, I R/I RC = e–KFF . Of the total PPFD intercepted by the canopy, the fraction K F/K due to leaves alone was estimated to be 85.0%–86.1% and the rest was contributed by woody organs.  相似文献   

18.
To improve the restoration of tropical rain forests, we tested the germination of seeds of Omphalea oleifera collected from soil (S) and from trees (T) in the 2001 dry season (Spring), at the beginning of a dry season (2005a, winter) and in the rainy season (2005b, winter). All seeds had high water content (WC, 31–33%), and the lipid content varied from 14 to 46%. Seedlings from seeds collected in 2001 were subjected to moderate water stress as a preconditioning treatment for severe stress. T-seeds collected in the dry season had high WC, rapid and high germination percentage; S and T-seeds collected in winter (2005) had also high WC but were dormant. GA3 (250 ppm) broke this dormancy. S-seeds collected in the dry season or at the beginning of it had relatively low WC and low and delayed germination. Some 2001 S-seeds produced albino seedlings. The critical water content for maintaining ecological longevity in these seeds was ∼15%. Seeds collected in 2005b that were dehydrated for 20 days in a moist and fresh atmosphere lost their viability, showing recalcitrant behavior. T-seeds with the lowest lipid content (2005a) after dehydration maintained low germination (15 ± 18%). In all samples the seed size varied widely and was not predictive of seed WC. Embryos taken from dehydrated seeds had two to four times higher WC than the seeds, but germination did not take place. Laboratory and field germination of dormant seeds showed that viability may be maintained for at least 2–3 months on a moist substrate (soil or agar). Moderate water stress at the seedling stage reduced the efficiency of biomass production. Response to this water stress was expressed more in physiological traits than in morphological characters, consequently biomass allocation was maintained and plants retained most of their morphological characteristics (root:shoot ratio, leaf area ratio, specific leaf area, leaf weight ratio). Moderate water stress did not increase the tolerance of seedlings to severe stress, causing leaf shedding and plant death. For restoration purposes we recommend that T-seeds be germinated immediately avoiding dehydration. The use of S-seeds could result in unhealthy seedlings. Seed recalcitrance and the response to moderate water stress restrict germination and establishment to small gaps, where this species naturally grows. We suggest that before introducing O. oleifera in restoration programs, a plant cover should be built to reduce soil water deficit. It is necessary to improve methods to increase potential seed longevity in storage.  相似文献   

19.
Micro-environmental factors viz., soil moisture and light intensity are important factors that affect natural regeneration in forests. These factors vary spatially depending on the overhead canopy density of the forest. The present study focused on studying the effect of variation of soil moisture and light intensity on natural regeneration of sal species (Shorea robusta) under different micro-environments due to overhead canopy of varying forest density. Experimental plots of 40m× 40m size were laid under different overhead canopy densities in a small sal forested watershed in the foot hills of Himalayas in Nainital District of Uttarakhand State, India. The plots were monitored on a long term basis for soil moisture at multi depths, light intensity and natural regeneration of sal. The results of the study revealed that the natural regeneration was highest under C1 (up to-0.30) canopy followed by C2 (0.30–0.50), and C3 (0.50–0.70) canopies. The C3 canopy showed the dying back of sal shoots over 4 years of study. The highest R2 value of linear regression between incremental score of plot regeneration and average soil moisture content was obtained as 0.156 for average soil moisture content during non-monsoon months at 100 cm depth. The R2 value between incremental score of plot regeneration and annual average light intensity was obtained as 0.688 which indicated that the regeneration is largely dependent on the light intensity conditions during the year. The multiple linear regression analysis between the incremental score of regeneration and the average light intensity and average soil moisture content revealed that that about 80% of variation in regeneration is explained by both the factors.  相似文献   

20.
A numerical model that predicts the stochastic dispersion associated with industrial kiln drying of timber was adapted to conventional drying and evaluated with experimental data. The theoretical aspects of the model are briefly explained, a selection of the calibration parameters was carried out, and a new empirical dispersion factor is proposed to account for all unknown sources of random behavior. The model was calibrated with six experimental runs of western hemlock and amabilis fir (116mm2 timbers) to an average moisture content (target) of 14%–20%. It was found that with implementation of the dispersion factor, the number of required simulations is considerably reduced, the calibration results are consistent for all the experimental runs, and the target moisture content along with its standard deviation can be well reproduced using the all-run average parameters.  相似文献   

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