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31.
Katsushige Shiraki Yoshiki Shinomiya Hirofumi Shibano 《Journal of Forest Research》2006,11(6):439-447
Numerical experiments of soil water movement and bedrock infiltration based on a simplified simulation method were conducted
to analyze watershed-scale rainfall-runoff processes. To verify the model accuracy, it was applied to a Minamitani watershed
(0.45 ha). The simulation was performed with 2.5-m space grids horizontally and five cells vertically. Results of long-term
calculation of this model proved that this simulation model is robust and demonstrated good computational water mass conservation.
Calculation results showed the best agreement with observed hydrographs and the number of groundwater levels simultaneously
when laboratory-tested soil hydraulic characteristics for topsoil were used and infiltration into bedrock was included in
numerical calculations. Numerical experiments show that bedrock infiltration generated a stable base flow and suppressed the
secondary discharge peak. The reproducibility achieved by observed soil hydraulic characteristics with the assumption of bedrock
flow demonstrates the effectiveness of the simulation model used in this article for analyses of watershed-scale soil water
movements. 相似文献
32.
Akio?InoueEmail author Marie?Miyake Tomohiro?Nishizono 《Journal of Forest Research》2004,9(4):319-324
An allometric model that explains the mechanism of the difference in the slope of the Reineke equation (A) among species was proposed based on the allometric relationships of mean tree height (H) to quadratic mean diameter D (H ∝ D
θ
) and stand density N (H ∝ N
δ
), i.e., A = θ/δ. The proposed model was fitted to Japanese cypress (Chamaecyparis obtusa Endl.) and red pine (Pinus densiflora) stands. The allometric exponents θ and δ were, respectively, 0.8995 and −0.5000 for cypress and 0.8612 and −0.6619 for pine. The difference between cypress and pine
was significant for δ but not for θ. Inserting the exponents into the model resulted in predicted slopes of −1.7991 for cypress and −1.3011 for pine. The difference
in the slope of the Reineke equation between the two species was produced by characteristics related to the tree crown, rather
than characteristics related to stem slenderness. The proposed model enables us to estimate the slope of the Reineke equation
from commonly measured stand attributes, such as mean tree height and quadratic mean diameter. Therefore, the proposed model
is expected to be practical and convenient for estimating the slope of the Reineke equation and for explaining the mechanism
of its variation among species. The model should be also accepted as a generalized model of the stand density versus quadratic
mean diameter relationship, whereas the original Reineke equation should be seen as a specific case of this model. 相似文献
33.
尾叶桉材积蓄积计算公式初探 总被引:5,自引:0,他引:5
从雷州林业局几个点收集2~11年生的尾叶桉生长资料和49株解析木材料,用数学回归方程推导出二元材积公式和蓄积公式,经验证,其精确度可靠 相似文献
34.
35.
CHANG Cheng JIN Peng ZHENG Wei KANG Hua-li DENG Meng-yang LI Shuang-fei WU Xiao-jing 《园艺学报》2015,31(1):12-17
AIM: To study the expression of Jagged2/Notch3 signaling molecules in pulmonary vascular wall of pulmonary hypertensive rats induced by monocrotaline. METHODS: SD rats were randomly divided into normal control group (C group,n=15), solvent control group (S group,n=15) and monocrotaline model groups (M group,n=15). The model of pulmonary hypertension was established by a single subcutaneous injection of monocrotaline (50 mg/kg). The rats in S group were given a single subcutaneous injection of the same dose of solvent. After 4 weeks, the pulmonary vascular remodeling was assessed by HE staining, and the mean pulmonary artery pressure (mPAP) and right ventricular systolic pressure (RVSP) were determined by right heart catheterization. The expression of Jagged2/Notch3/Hes5 molecules in the pulmonary vascular wall was detected by immunohistochemical method and real-time PCR. RESULTS: Compared with S group and C group, the percentage of medial wall thickness of smaller arteries in model group increased significantly (P<0.01). The levels of mPAP and RVSP in M group were significantly higher than those in S group and C groups (P<0.01). The results of real-time PCR showed that the expression of Jagged2, Notch3 and Hes5 was significantly increased in M group compared with S group and C group. The data from immunohistochemical detection indicated that Jagged2 mainly expressed in the intima of small lung artery, Notch3 and Hes5 mainly expressed in the medial smooth muscle cells. Compared with S group and C group, the expression of Jagged2 and Notch3 was significantly increased in the lung small arteries of M group. CONCLUSION: The activation of Jagged2/Notch3 signaling pathway might play an important role in the formation of pulmonary hypertension. 相似文献
36.
利用广东高要和广西扶绥两地14个2~10年生桉树林分样地共287株样木,研究短轮伐期桉树人工林个体林木特征指标,并比较现有广西良种桉二元带皮和去皮材积公式估算个体林木材积的准确性,分析不同年龄、林分和径阶林木的出材率。结果表明:带皮和去皮林木的胸高形数为0.504±0.004 2和0.529±0.004 4、实验形数为0.410±0.002 4和0.427±0.002 7、形率为0.657±0.003 4和0.690±0.003 6、高径比为1.22±0.017和1.43±0.019。用广西良种桉二元带皮和去皮材积公式估算单株林木带皮和去皮材积与实际材积高度相关(r>0.99),但估算值普遍偏低,平均分别小3.7%和21.0%;尤以用带皮材积公式估算去皮材积比用去皮材积公式估计要准确,平均只小2.3%。如以6年生以上样地和尾径4 cm以上的去皮林木为实际出材,5个相关样地林分平均出材率为(73.3±4.31)%,最小为54.6%,最大为81.5%。 相似文献
37.
Growth and yield models were developed for individual tress and stands based on336 temporary plots with 405 stem analysis trees of dahurian larch(Larix gmelinii(Rupr.)Rupr.)plantations throughout Daxing’anling mountains.Several equations were selected using nonlinearregression analysis.Results showed that the Richards equation was the best model for estimatingtree height,stand mean helght and stand dominant height from age; The Power equation was thebest model for prediction tree volume from DBH and tree height; The logarithmic stand volumeequation was good for predicting stand volume from age,mean height,basal area and other standvariables.These models can be used to construct the volume table, the site index table and other for-estry tables for dahurian larch plantations. 相似文献
38.
Richards林木生长模型及其适用性 总被引:3,自引:0,他引:3
该文简述了Richards生长方程的可塑性,以毛白杨、华北落叶松、刺槐与斑克松的生长资料,讨论了描述林木生长过程的适用性。 相似文献
39.
40.
We derived an allometric model of the height–diameter curve for even-aged pure stands, which was a modification of the earlier
model proposed by Inoue (2000a). An individual-dependent allometric equation was used as the height–diameter curve. Using
the discriminant analysis method, all trees composed of a stand were stratified into upper and lower trees. It was assumed
that both relationships between mean tree height H
m
and upper tree height H
u
and between mean DBH D
m
and mean DBH of upper trees D
u
could be described by the time-dependent allometric power equations. The height–diameter curve showed an average relationship
between tree height and DBH of a given stand at a given time, and hence it could be assumed that the height–diameter curve
contained two points (D
m
, H
m
) and (D
u
, H
u
). With these assumptions, we derived an allometirc model of height–diameter curve, which allowed the coefficients of the
curve to be estimated from mean tree height and mean DBH. The proposed model was fitted to Japanese cedar (Cryptomeria japonica D. Don) data. The error ratio of the allometric model ranged from 2.254% to 13.412% (mean = 6.785%), which was significantly
smaller than that of the earlier model. When the error of mean tree height was ±1.0 m or less, the effect of the error of
mean tree height on the error ratio was comparatively small. This suggested that the error of ±1.0 m in mean tree height could
be accepted in the estimation of height–diameter curve using the allometric model. These features enable us to combine the
allometric model with Hirata’s vertical angle-count sampling or growth models. In conclusion, the allometric model would be
one of the most practical and convenient approaches for estimating the height–diameter relationship of even-aged pure stands. 相似文献