Crown density control is one of the main activities in forest management. For the prediction of tree growth, it is important to consider the crown length, leaf biomass, and other canopy parameters as a photosynthetic organ. We estimated the lengths of canopies on the basis of a Digital Surface Model (DSM) and Digital Elevation Model (DEM) obtained from airborne Light Detection and Ranging (LiDAR) data and examined the accuracy of the estimates in even-aged stands. Cryptomeria japonica and Chamaecyparis obtusa stands were selected for analysis. The study site was the University Forest in Chiba, Japan, which is managed by the University of Tokyo and has stand densities between 350 and 4,000 trees ha^<-1>. First, we calculated the DSM and DEM for the University Forest in Chiba for the analysis of canopy information. We established 12 circular sample plots in Cryptomeria japonica and Chamaecyparis obtusa stands and measured the crown length of the dominant trees in each plot. Second, we estimated the crown length of the dominant trees in each plot using the DSM and DEM obtained from airborne LiDAR data. Finally, we compared crown lengths obtained from airborne LiDAR data with crown lengths obtained from ground surveys and checked the accuracy of this methodology. The crown lengths obtained from airborne LiDAR data were highly correlated with those obtained from ground surveys (coefficient of determination=0.95; root mean square error (RMSE)=0.67). Thus, airborne LiDAR accurately measured crown length, regardless of stand density.

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The objective of this study was to infer the most important gradients influencing species composition and abundance of colonizing native trees (CNT) in an unthinned Japanese cedar (Cryptomeria japonica D. Don) plantation in northern Japan. A 0.84-ha (60×140m) plot was established in the stand and was subdivided into a total of 42 subplots (20×10m each). For each tree >3cm in diameter at breast height (DBH) in each subplot, we recorded the species and DBH. Path analysis with structural equation modeling was performed to analyze the correlation and causal relationships between slope characteristics, soil properties and vegetation attributes of the set of subplots. Species composition of CNT was strongly affected by site conditions along relatively short gradients of slope aspect and soil water content, but stand height had little effect on species composition. In contrast, the abundance of CNT was strongly affected by site conditions along relatively short gradients of slope aspect and soil water content, and stand height also significantly affected abundance. The contrasting patterns of variation between species composition and abundance of the CNT may reflect the fact that the mortality rate of CNT at the adult tree stage varies according to vertical stand structure rather than to interspecific differences in survival patterns. In conclusion, recruitment patterns from the juvenile tree stage for each species were related principally to species composition and abundance of CNT, and site-specific mortality at the adult stage was also significantly related to the abundance of CNT.

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Forest resources are an important part of natural resources and terrestrial ecosystems. With the quick economic development and the national power improvement, China has been increasing the investment in forestry, including many key forest projects, natural reserves and forest parks. However, the lack of adequate and reliable capital input has become a major bottleneck to the development of ecological forestry in China. Although the Chinese government has established the policy to encourage mutual investment in forestry by collectives and individuals to solve the problem, farmers, the subjects of forest management haven't the economic competence to invest in forestry. This has reduced the enthusiasm of farmers' forest management and has been an obstacle of forestry development. For this reason, the countermeasures should be implemented as soon as possible in order to improve farmers' income, and make them play important role in the forestry development.

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Rubber trees (Hevea brasiliensis) in Cambodia are important sources for not only natural rubber but also wood products. This study was conducted to set up stem volume equations to estimate the stand volume and the volume increment for rubber trees in Cambodia. Krek Rubber Plantation located in Kompong Cham Province was selected for study area. Sixty trees of the clone PR107 at the age of 36, 44, 45 and 46 were felled and cut into segments of one meter long to formulate the volume equation. The DBH and total height of 450 standing trees (15 plots) at different ages (6-10 and 36-48) were measured to estimate volume per hectare and the mean annual increment (MAI). This study revealed that the volume equation for standing rubber trees clone PR107 is V=0.00018381 D^<2.23961> H^<0.15334> or V=0.00024884 D^<2.29535> where V is the over bark volume (m^3), D is diameter at breast height (cm), H is total height (m). Using the two-variable equation, rubber wood volume at the rotation length of 25-30 years was estimated at about 240 - 270m^3 ha^<-1> with the MAI of 9.33 m^3 ha^<-1> yr^<-1>.

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To investigate the quantitative relationships between increase in stem volume (SVI) and sunny crown dimensions for Hinoki cypress (Chamaecyparis obtusa ENDL.), we calculated the SVI per unit sunny crown dimension using three different sunny crown dimensions [i.e., volume (SCV), surface area (SCSA), and volume increase (SCVI)]. Samples were collected from six stands of even-aged Hinoki cypress in Nara Prefecture, Japan. For each SVI per sunny crown dimension, the mean among stands was compared. The SVI/SCV did not vary among the sampled stands, whereas the SVI/SCSA and SVI/SCVI varied with the stage of growth. Although our observed mean SVI/SCV was slightly larger than that in another region, the minimal difference observed between regions suggests that the SVI/SCV can be generally used to estimate the SVI of Hinoki cypress. Thus, SVI/SCV is an appropriate coefficient with which to estimate SVI.

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