The vertical distribution of the cross-sectional area increment of the lower trunk in aged Sugi (Cryptomeria japonica) trees was analyzed using annual ring data from disks. We collected data from three approximately 90-year-old mature plantations under different density management and three old-growth stands of 160 years or more. Of the nine sample trees in the thinning experiment plots, only three had significantly higher cross-sectional area increments at a relative height of 0.2 × tree height (0.2h) than the mean cross-sectional area increment. This result did not strongly support the hypothesis that several trees in mature stands that are thinned regularly may show a heightening trend in the cross-sectional area increment of the lower trunk. In contrast, the cross-sectional area increment at 0.2h was significantly higher than the mean cross-sectional area increment for all three sample trees in the old-growth stands. A generalized linear mixed model with the presence or absence of a heightening trend in the cross-sectional area increment of the lower trunk as a response variable was used for 20 sample trees. The results showed that the model with the ratio of height to diameter at breast height (H/D ratio) and relative spacing index (Sr) as fixed effects was optimal. The probability of trees showing a heightening trend in the cross-sectional area increment of the lower trunk increased with a lower H/D ratio and a higher Sr at the most recent values. We estimated that if stand density is maintained at an Sr≥19%, where the forest canopy is sparse, a heightening trend of cross-sectional area increment at the lower part of the trunk occurs in trees with a H/D ratio of ≤71.
Semi-captive Asian elephants (Elephas maximus) engaged in forestry activities in Myanmar account for 20% of all captive and semi-captive Asian elephants in the world, and are important for both forestry and the conservation of Asian elephant populations. Understanding moving behavior of the semi-captive elephants is required to sustain them. Our specific goals are 1) to determine the moving range during free time, and 2) to determine the hourly moving distance during skidding and when off duty. Three elephants were fitted with handheld global navigation satellite systems with the signals of global positioning system to collect data on their movements. The elephants were generally located between 0.534 and 0.875 km from the camp with temporary housing of the elephant handler when not skidding (i.e., free time) and between 1.365 and 1.372 km when skidding (i.e., work time). The hourly moving distance during free time (0.622–0.655 km) and work time (1.522 and 1.629 km) did not differ greatly from the hourly moving distance of wild Asian elephants (0.010–1.500 km). The elephants remained within 0.875 km of the camp of the elephant handler, and some variation in movements among individuals was observed during free time. Thus, the conservation of forest in areas near the camp is important for the well-being of these elephants.
In this study we examined the validity of the canopy closure curve as a reference in relation to light conditions and demonstrated the applicability of the curve to different thinning types. An even-aged sugi (Cryptomeria japonica) plantation of 91 years was thinned heavily and transformed to a two-storied stand by underplanting with sugi and hinoki cypress (Chamaecyparis obtusa) seedlings. Three initial sample plots were selected in the stand before thinning. After the conversion, five permanent sample plots were established and both overstory and understory trees were measured up to the age of 118 and 28 years, respectively. The canopy closure curve was estimated from measurements collected in the initial sample plots and crown density (i.e. the ratio of overstory productivity to the maximum stand productivity) was calculated based on the canopy closure curve as a reference. To validate the curve, we derived three time points from the measurements collected in the permanent sample plots: one when the trajectory of stem density and stand volume of the overstory trees intersected the canopy closure curve, one when the relationships between the volume of individual overstory trees and their growth changed, and one point when the growth of understory trees dropped. The first of these time points coincided with the second and third time points. This means that dominant overstory trees suppressed smaller overstory trees and overstory trees constrained the growth of understory trees because of light reduction when the canopy closed. The canopy closure curve was found to be a valid way to assess light controlling the growth of understory trees. Furthermore, we generated virtual thinning data from the measurements taken in the initial sample plots for different thinning types. We obtained the canopy closure curve for these. We plotted the trajectory of stem density and stand volume in relation to the thinning as well as the canopy closure curve to demonstrate the applicability of the canopy closure curve. The thinning simulation showed sufficient effect to demonstrate that there was no need for additional accretion cutting.
Most survival analyses in forest science have been applied to planted forests where tree age usually had no dispersal on one stand, while there have been few reports about the age-based survival analyses in natural forests. The purpose of this study was to perform survival analyses of individual tree populations in natural forest stands to evaluate the matured states of forest stands. We used a combination of tree-ring and census data from the three preserved permanent plots in pan-mixed and sub-boreal natural forests, Hokkaido, northern Japan. All the living trees (diameter at breast height ≥ 5 cm in 1989) were targeted to identify tree ages using a RESISTOGRAPH. Periodical tree age data with a 10-year age class were used during the observation periods of 1989–1999, 1999–2009, and 2009–2019, and all the changes (i.e., death and new ingrowth) during the periods were recorded. In the analyses, first, we applied survival analyses to find out multi-temporal age distributions and non-parametric estimates. Secondly, we applied parametric Weibull distributions to calculate age-related metrics such as mean lifetime and mean age of stands. Finally, we evaluated these calculated metrics from the viewpoints of matured states of forest stands. The results of non-parametric survival analyses showed the age distribution of multi-modal and exponential shapes. We also found the differences in survival probabilities among periods were not significant except for one plot. We also compared the relationship among estimated mean lifetime, biological lifetime, and mean age of stands derived from parametric survival analyses with the Weibull distribution and evaluated the matured states of stands considering all these aspects. It was implied that the study stands might not get enough matured yet, but some plots showed further progress toward the matured state than others.
A fair, democratic standard development process is central to ensuring the credibility and legitimacy of forest certifications built on private governance. This study reports the implementation of the multi-stakeholder process for developing the FSC national forest stewardship standard of Japan and analyzes the factors affecting the discussion for collective decision making. In particular, this study highlights the issue of radiological safety and indigenous peoples' rights, on which the discussion for developing certification requirements especially contested due to considerable gaps between the international standards and the existing legal framework or practices in Japan. The overall discussion was characterized by the general conflict of opinions between certificate holders advocating for pragmatic requirements in line with existing practice and the civil society supporting robust standards. The factors that are considered to have affected the FSC national standard development in Japan include stakeholder relations, presence of competing scheme, governance structure, FSC's value proposition, and some personal leadership. Among them, the pre-set value proposition seems to be the most powerful factor that sets the priority in decision-making and determines the outcome. For this multi-stakeholder process, revisiting the shared value of FSC resulted in setting a priority on the certification's credibility over market uptake and many certification requirements at the level of international standards. In the future, comparison with other multi-stakeholder processes conducted in different contexts will further reveal factors affecting the deliberative and decision-making process and outcome.
The "preserved tree system" and "preserved forest system" aim to preserve trees and forests in cities in Japan, and are operated by local governments. We conducted a questionnaire of the operators of the preserved tree system to examine their awareness of the systems in Nagoya (215 operators) and Shizuoka (60 operators), and clarified the relationships among operators, local governments, and community residents not involved in tree management. Questionnaires were returned by 117 (Nagoya) and 30 (Shizuoka) operators. The results were as follows: 1) Although local governments and operators agreed on the goals of the system (green preservation, improving aesthetic appeal, and preservation of trees with historical and cultural value), there were concerns over the associated costs and economic burden faced by the management; 2) There was a risk of conflict between the operators and community residents because calls for preservation by neighboring residents increased when operators stopped tree management. For sustainable preservation of designated trees in the local environment, promotion of cooperation between community residents and operators is crucial.
This study proposes a way to apply stem analysis to pollarded trees and to show the relationship between the growth of a pollarded tree and topping the main trunk. As an example, we examined a pollarded wild sugi (Cryptomeria japonica) tree. The study tree was in a sugi plantation with scattered wild sugi trees in Tsunagi hamlet, Aga Town, Niigata Prefecture, Japan. The main trunk was thought to have been broken by heavy snow. The part of a coppiced tree that differs most from a single-stemmed tree is the area that connects the remaining trunk and the pollard shoots. Examining disks taken by slicing through part of the tree allows the budding location and timing of the formation of the shoots to be determined from the distribution of annual rings. This study showed that losing the upper part of the trunk had a great effect on the secondary growth of the remaining trunk, suggesting that topping a main trunk also affects the secondary growth of the remaining trunk. Competition between the shoots was found, suggesting that in order to obtain large, high quality logs from the remaining trunks, shoots that are likely to die are pruned before they put on much growth.
A case study on the effect of Japanese larch ( Larix kaempferi Carr.) arable land windbreaks on the reduction of wind damage in Kamioribe District, Shihoro Town, eastern Hokkaido, Japan, is reported. Wind damage occurred on May 8, 2016. Buds of larches were supposed to be just opened, and the leaves on short shoots were still extending at that time. The percentage of severe damage was high on arable lands outside sheltered areas. In contrast, it was low on lands within areas 15 to 20 times the heights of windbreaks leeward to Japanese larch arable land windbreaks. These differences were statistically significant. The results of this study indicate that Japanese larch arable land windbreaks are effective for the reduction of wind damage during the early spring cultivation season, regardless of if its buds are closed or its leaves are not fully extended.
We identified tree species based on leaf images with a convolutional neural network (CNN). We sampled approxi mately 200 to 300 leaves per tree from five tree species at Kyoto University Campus. Twenty to thirty 1.0 × 1.0 cm (256 × 256 pixel) leaf images were taken per leaf, from which 10,000 leaf images (2,000 × 5 individual tree species) were prepared for the sample data. Color, grayscale, and binary images were used as image types. We constructed 36 learning models using based on differences in learning patterns, image types, and learning iterations. Performance evaluation of the proposed model was conducted using the Matthews correlation coefficient (MCC). Both training and test data had high classification accuracy. The mean MCC of the five tree species ranged from 0.881 to 0.998 for the training data and 0.851 to 0.994 for the test data. Classification accuracy was generally high for color images and low for grayscale images. We found that there were many cases where Cinnamomum camphora was misclassified as Quercus myrsinifolia , or Quercus myrsinifolia was misclassified as Quercus glauca ; most Quercus glauca , Ilex integra , and Pittosporum tobira trees were correctly classified using the training data; and misclassification using test data for Ilex integra was very low.
Several methods are available to assess the plantation timber volume at their maturity. However, most of those methods can not be applied to the teak ( Tectona grandis L.f) plantations of Sri Lanka, due to different site qualities and different management practices since planting. Therefore it is essential to carry out a comparative study of commercial log production managed under different conditions. For this purpose, the use of height-diameter and relative taper curves for estimation and prediction of planted teak stands in dry and intermediate zones of Sri Lanka were evaluated. Even-age mature plantations which are subjected to clear fell was selected randomly. Standing tree measurements of 164 trees were taken at three sites to build up the height-diameter curve. At the same time, 158 trees were felled and took diameter measurements along the felled log to construct the relative taper curve. The resulted models are use ful in generating accurate and localized predictions of standing tree height, total timber volume, commercial timber volume which would eventually lead to better estimations on differently managed teak plantation sites. By measuring the diameter at breast height alone, the developed log diameter-length tables could estimate the commercial log length according to specific diameter values which would finally lead to better commercial log estimation to compete with increasing demand along with different site conditions.
Green space is important for childhood development, particularly in developing countries. The city of Malang, Indonesia has experienced steady economic and population growth in recent years, but green space area in the urban environment has been declining. In this study, we elucidated the status of green space accessible to children in Malang, and discussed ways of improving green space use. We identified green spaces around 291 elementary schools using satellite remote sensing. A RapidEye satellite image, which covered the study area with a 5-m ground sample distance, was acquired on May 20, 2015. From this image, the area of green spaces within 1 km radius circles of elementary schools were calculated. The total area of green space in the city was 45.439 km2, 41.3% of the total city area. Smaller green spaces were located near the city center, whereas larger green spaces were located in the southeastern part of the city. The green space ratio within 1 km of 96 schools was less than 15%, and it was 15–30% around 104 schools. Overall, there were few green spaces within walking distance of schools in Malang. The green space ratio in the city center was also low. Green spaces in the city should be maintained, and additional opportunities should be provided for children to access green spaces.
Local people's involvement in forest management in Indonesia was studied in a context of a community-based forest management program named Pengelolaan Hutan Bersama Masyarakat (PHBM), which emerged from the state-owned forest company, Perhutani. On Java Island, this program has been spreading since 2003 and it was hoped that it would help to increase local people's income by giving them access to the forest, to assist in the thinning process and to cultivate intercropping. This study aimed to observe the impacts of people's involvement in the PHBM program on their economic wellbeing. The study was conducted over three research phases, in 2005/2006, 2006/2007, and 2008/2009, in Desa Ciomas village, Bogor District, West Java Province and through follow-up research performed in 2016 to observe more recent conditions and establish the continuity of the previous research. The results showed that local people in Desa Ciomas were highly interested in PHBM and the benefits that it offered, with an expectation of additional income. The optimal income was not realized in some cases, including when large-scale farming necessitated farming system that replied on hired labor which is known to be less productive than family labor. PHBM should be able to contribute to local people's income by empowering them with respect to both on- and off-farm activities.
The harvesting of timber with a view to the sustainable use of timber resources is called yield regulation. One problem with using this simple indicator is the lack of information it provides for forest management. The first half of this paper will trace how indicators have shifted with time. As a result of looking back on the past, it was confirmed that a simple index was effective for preventing overcutting. The second half of this paper will outline the revolutionary changes introduced by LiDAR. The main findings were as follows. Firstly, because LiDAR has made it possible to measure tree heights, the fundamental data used in forest management will switch from diameter of breast height to tree height in the near future. Secondly, because population data of both trees and ground surface can be obtained through the analysis of LiDAR data, the base unit of forest management will switch from forest stand in nature to forest land artificially separated by squares like a grid. And lastly, because we can obtain both DSM and DTM from LiDAR data, we now have access to precise population data about standing trees and ground surface. This opens up new opportunities to help forest managers in their work. LiDAR has not only brought about a great technical innovation in the field of forest management, but it has also ushered in a major revolution in the philosophy of forest management.
In recent years, unmanned aerial vehicles (UAVs), which have been internationally developed and utilized in many fields, has also attracted people's attention in the forestry service. Using UAV systems as a data acquisition instrument and a monitoring tool, it can be expected to solve some issues in conventional forest resource inventories and enabling more efficient research. This study was conducted using structure from motion (SfM), which is a photogrammetric range imaging technique. This is accomplished using aerial photography with a UAV in the University forest and consists of: 1) generation of a 3D model of photographed objects, 2) estimation of tree height and DBH, 3) evaluation of the estimation accuracy, and 4) comparisons to measurement errors between two aerial photography sets. The result showed that root mean squared error (RMSE) in the estimated tree height was 1.58 m and RMSE in the estimated DBH from a relational expression between tree height and DBH was 3.88 cm, and RMSE in the estimated tree height between the first and second photography was 0.21 m.
The conservation of selectively logged tropical forests has received increasing attention, especially under the REDD+ scheme of the United Nations Framework Convention on Climate Change. However, knowledge of the structure of large-scale logged forests remains limited, especially in seasonally dry tropical regions, while there have been many studies on intact old-growth closed-canopy tropical forests. In this study, data from 327 plots were used in a large-scale forest inventory with systematic sampling covering 139,360 ha to reveal the condition of selectively logged mixed-deciduous forest managed traditionally under the Myanmar selection system (MSS). The overall averages (±SE) for the trees > 10 cm DBH were 140 ± 4.95 trees/ha for tree density, 6.18 ± 0.26 m2/ha for basal area and 66.2 ± 3.17 Mg/ha for aboveground biomass. These values are lower than or close to the lower end of the reported values in undisturbed or even disturbed tropical forests. There were very few harvestable large trees of commercial species. We conclude that there has been widespread large-scale forest degradation in the traditionally logged forest of our study site. The possible reasons for forest degradation include the shorter cutting-cycle than the MSS-standard of 30 years, more illegal logging for timber than legal logging, and local demand for charcoal. Restoration of the degraded forests should be prioritized, together with control of illegal logging.
