The artificial pure and mixed Korean pine (Pinus koraiensis) forests were investigated at Dailing Forestry Bureau in Xiaoxing'an mountains from 1990 to 1992. Depending on the distance between the samplings of Kore...The artificial pure and mixed Korean pine (Pinus koraiensis) forests were investigated at Dailing Forestry Bureau in Xiaoxing'an mountains from 1990 to 1992. Depending on the distance between the samplings of Korean pine and their neighbor trees, the neighbor tree height, the size of neighbor tree canopy, and dimension of neighbor tree. The forest structure was classified into three types: (1) prowth of a tree in the light (open), (2) Growth of a tree in the canopy gap (Gap), (3)Growth of a tree under broad-leaved tree canopy. The frequeney, height, and age of stem divergence of Korean pine tree were investigated by sampling trees. The temporal and spatial model of the tree growth was applied on basis of the height of stem divergence, ratio of height and DBH, and character of tree stem.The morphology and growth character of Korean pine trees during different development stage were forecasted.展开更多
Huashan pine (Finus armandii Franch) is a poential species for dendroclimatic study. Ring-width cores were sampled for four stands of two sites from the eastern extreme of the Qinling Mountains. The ring-width chronol...Huashan pine (Finus armandii Franch) is a poential species for dendroclimatic study. Ring-width cores were sampled for four stands of two sites from the eastern extreme of the Qinling Mountains. The ring-width chronologies developed in this study cover a maximum Period from A.D. 1359 t0 1992 and show high common chronology variance over the common period 1911-1960.All the chronologies are significantly correlated with all others, and the degree of correlation appears related to tree age. Response function analyses reveal that from 41 to 75 Percent of chronology variance can be accounted for by monthly mean air temperature and monthly total precipitation. A sufficiently strong correlation of ringwidth index with May and June rainfall and June temperature exists, implying soil moisture to be a limiting factor for Huashan pine growth. The association displayed by response diagrams between narrow rings, low precipitation, and high temperature during spring and early summer indicates a promising potential of ring widths for reconstruction of spring drought for the study area.展开更多
The alien woody legume, black locust (Robinia pseudoaca-cia), has invaded Japanese black pine (Pinus thunbergii) forests located in Japan’s coastal plain and hill regions where gaps are formed in pine forests aft...The alien woody legume, black locust (Robinia pseudoaca-cia), has invaded Japanese black pine (Pinus thunbergii) forests located in Japan’s coastal plain and hill regions where gaps are formed in pine forests after nematode infestation. Nitrogen fixation by legumes acceler-ates N cycling in forest ecosystems. We studied temporal change in the annual tree-ring resolution N stable isotope composition (δ15N, a per mil deviation of δ15N/14N ratio, relative to atmospheric N2δ15N=0‰) at two natural locations of Japanese black pine forest with black locust that differed in the time since black locust establishment (Shohnai in north-east and Kita-Kyushu in southwest Japan). Analyzed tree-rings covered the period from 1990/1992 to 2009. N acquisition by Japanese black pine from black locust N input to the soil was evidenced by temporal shifting of N stable isotope composition on the annual pine tree rings. With pro-gressive development of the forest stand,δ15N values of earlier tree-ringsδ15N of -5‰) from black pine associated with black locust shifted to-wards values similar to those of black locustδ15N values nearly to-1‰), which suggests acquisition of N by N2 fixation (Shohnai site). In con-trast, in a forest where black locust had settled for two or three genera-tions, in a black pine stand (Kita-Kyushu site), longer periods of N en-richment in the soil were reflected in the elevated tree-ringδ15N values of newly established black pine trees. Based on tree-ringδ15N data from the Shohnai site, we determined that about 10 years after black locust establishment, soil N had already been enriched by black locust N, this, in turn, contributed to N fertilization of surrounding trees in mixed stands.展开更多
Accurate and efficient estimation of forest growth and live biomass is a critical element in assessing potential responses to forest management and environmental change. The objective of this study was to develop mode...Accurate and efficient estimation of forest growth and live biomass is a critical element in assessing potential responses to forest management and environmental change. The objective of this study was to develop models to predict longleaf pine tree diameter at breast height (dbh) and merchantable stem volume (V) using data obtained from field measurements. We used longleaf pine tree data from 3,376 planted trees on 127 permanent plots located in the U.S. Gulf Coastal Plain region to fit equations to predict dbh and V as functions of tree height (H) and crown area (CA). Prediction of dbh as a function of H improved when CA was added as an additional independent variable. Similarly, predic- tions of V based on H improved when CA was included. Incorporation of additional stand variables such as age, site index, dominant height, and stand density were also evaluated but resulted in only small improvements in model performance. For model testing we used data from planted and naturally-regenerated trees located inside and outside the geographic area used for model fitting. Our results suggest that the models are a robust alternative for dbh and V estimations when H and CA are known on planted stands with potential for naturally-regenerated stands, across a wide range of ages. We discuss the importance of these models for use with metrics derived from remote sensing data.展开更多
The thesis for the Doctorate consist of two parts. The first is to study on structure, dynamics and tree growth of natural Korean pine forest. The second is to research for tree architecture, growth and stand structur...The thesis for the Doctorate consist of two parts. The first is to study on structure, dynamics and tree growth of natural Korean pine forest. The second is to research for tree architecture, growth and stand structure of artificial Korean pine (Pinus koraienstj) forcsts.The thesis comparcs the stand structure, process of regeneratio n, and various tree growth patterns between natural forests and artificial forests. Its purpose is to give a basis for forest management and silviculture. The study was carried out in Liangshui Experimental Forest Farm, which is located in the southern Xiaoxing’an Mountains.展开更多
The article presents the first direct evidence of the influence of supernova flashes on the biosphere. Geochemistry and paleontology have not yet provided convincing data on the life response to disasters in the Milky...The article presents the first direct evidence of the influence of supernova flashes on the biosphere. Geochemistry and paleontology have not yet provided convincing data on the life response to disasters in the Milky Way Galaxy. This gap was eliminated through tree ring analysis of bristlecone pine from the Cordilleras responded to seven supernova outbursts in 185-1604 AD. The author used the superposed epoch method to process data at the 11 longest dendrochronologies, based on the results of measurement of annual growth of about 300 trees. The main finding is the growth depression in high-mountain population caused by supernova outbursts lasted for 20 - 30 years after the event. Moreover, in most cases, drastic growth reduction occurred one year prior to the event. In some cases, the annual tree ring increment exceeded the normal range many years after the event, and, consequently, it could be concluded that plant response was associated with the ozone layer depletion.展开更多
Thinning of Korean pine (Pinus koraiensis Sieb. et Zucc.) is used to facilitate timber and cone production. The present study in Northeast China investigated the effects of thinning intensity on individual tree growth...Thinning of Korean pine (Pinus koraiensis Sieb. et Zucc.) is used to facilitate timber and cone production. The present study in Northeast China investigated the effects of thinning intensity on individual tree growth, temporal variation in cone yield, and seed quality in Korean pine plantation. In 2005, five thinning intensity levels (none, extreme, heavy, moderate and light) were set in 15 permanent plots in a 32-year-old Korean pine plantation at Mengjiagang Forest Farm, Jiamusi City, Heilongjiang Province. We recorded tree growth and seed cone production from 2013 to 2016, i.e., from 8 to 11 years after thinning. Except for height growth, thinning increased tree growth (diameter at breast height and crown size) and improved cone yield. The extreme thinning treatment (to 300 trees per hectare) resulted in the largest tree diameter, tree volume, crown size and 4-year cone production per tree. The highest cone yield per tree in the mast year (2014) was observed when stands were thinned to 500 trees per hectare (heavy thinning). Although the best cone and seed quality and the largest cone and seed mass per tree were recorded in the heavily thinned stand, no significant differences were found between heavy and moderate thinning stands (750 trees per hectare). At the stand level, the moderately thinned stand had the highest basal area, stock volume and seed cone production per stand. Our results suggest that thinning to 750 trees per hectare will improve timber and cone productivity in 40-year-old P. koraiensis stands.展开更多
Ponderosa pine (Pinus ponderosa Laws.) has been planted widely in the Great Plains. Recommendations based on a 1968 study were to use material from south central South Dakota and north central Nebraska. A second test ...Ponderosa pine (Pinus ponderosa Laws.) has been planted widely in the Great Plains. Recommendations based on a 1968 study were to use material from south central South Dakota and north central Nebraska. A second test to further delineate seed sources (provenance/families) in this region was established in 1986. This paper reports results for survival, height, diameter, and D2H measurements in Kansas at 15 years. Results identify a wide range of suitable families within the Great Plains region.A majority of the tested sources performed well especially those from central Nebraska. Those sources from eastern Montana and western Nebraska performed poorly where environmental or geographic conditions were the poorest, thus verifying the original recommendations.展开更多
为解决山地地形起伏大、无人机飞行高度高导致图像中尺度小且纹理模糊的松枯死木识别困难问题,该研究提出了一种在特征层级进行超分辨率重建的YOLOv5松枯死木识别算法。在YOLOv5网络中添加选择性核特征纹理迁移模块生成有细节纹理的高...为解决山地地形起伏大、无人机飞行高度高导致图像中尺度小且纹理模糊的松枯死木识别困难问题,该研究提出了一种在特征层级进行超分辨率重建的YOLOv5松枯死木识别算法。在YOLOv5网络中添加选择性核特征纹理迁移模块生成有细节纹理的高清检测特征图,自适应改变感受野的机制分配权重,将更多注意力集中在纹理细节,提升了小目标和模糊目标的识别精度。同时,使用前景背景平衡损失函数抑制背景噪声干扰,增加正样本的梯度贡献,改善正负样本分布不平衡问题。试验结果表明,改进后算法在交并比(intersection over union,IoU)阈值取0.5时的平均精度均值(mean average precision,mAP50)为92.7%,mAP50~95(以步长0.05从0.5到0.95间取IoU阈值下的平均mAP)为62.1%,APsmall(小目标平均精度值)为53.2%,相比于原算法mAP50提高了3.2个百分点,mAP50~95提升了8.3个百分点,APsmall提升了15.8个百分点。不同算法对比分析表明,该方法优于Faster R-CNN、YOLOv4、YOLOX、MT-YOLOv6,QueryDet、DDYOLOv5等深度学习算法,mAP50分别提高了16.7、15.3、2.5、2.8、12.3和1.2个百分点。改进后松枯死木识别算法具有较高精度,有效缓解了小目标与纹理模糊目标识别困难问题,为后续疫木清零提供技术支持。展开更多
TREE submodel affiliated with TREEDYN was used to simulate biomass dynamics of Masson pine (Pinus massoniana) forest under different managements (including thinning, clear cutting, combining thinning with clear cut...TREE submodel affiliated with TREEDYN was used to simulate biomass dynamics of Masson pine (Pinus massoniana) forest under different managements (including thinning, clear cutting, combining thinning with clear cutting). The purpose was to represent biomass dynamics involved in its development, which can provide scientific arguments for management of Masson pine forest. The results showed the scenario that 10% or 20% of biomass of the previous year was thinned every five years from 15 to 40 years made total biomass of pine forest increase slowly and it took more time to reach a mature community; If clear cutting and thinning were combined, the case C (clear cutting at 20 years of forest age, thinning 50% of remaining biomass at 30 years of forest age, and thinning 50% of remaining biomass again at 40 years of forest age) was the best scenario which can accelerate speed of development of Masson pine forest and gained better economic values.展开更多
文摘The artificial pure and mixed Korean pine (Pinus koraiensis) forests were investigated at Dailing Forestry Bureau in Xiaoxing'an mountains from 1990 to 1992. Depending on the distance between the samplings of Korean pine and their neighbor trees, the neighbor tree height, the size of neighbor tree canopy, and dimension of neighbor tree. The forest structure was classified into three types: (1) prowth of a tree in the light (open), (2) Growth of a tree in the canopy gap (Gap), (3)Growth of a tree under broad-leaved tree canopy. The frequeney, height, and age of stem divergence of Korean pine tree were investigated by sampling trees. The temporal and spatial model of the tree growth was applied on basis of the height of stem divergence, ratio of height and DBH, and character of tree stem.The morphology and growth character of Korean pine trees during different development stage were forecasted.
文摘Huashan pine (Finus armandii Franch) is a poential species for dendroclimatic study. Ring-width cores were sampled for four stands of two sites from the eastern extreme of the Qinling Mountains. The ring-width chronologies developed in this study cover a maximum Period from A.D. 1359 t0 1992 and show high common chronology variance over the common period 1911-1960.All the chronologies are significantly correlated with all others, and the degree of correlation appears related to tree age. Response function analyses reveal that from 41 to 75 Percent of chronology variance can be accounted for by monthly mean air temperature and monthly total precipitation. A sufficiently strong correlation of ringwidth index with May and June rainfall and June temperature exists, implying soil moisture to be a limiting factor for Huashan pine growth. The association displayed by response diagrams between narrow rings, low precipitation, and high temperature during spring and early summer indicates a promising potential of ring widths for reconstruction of spring drought for the study area.
文摘The alien woody legume, black locust (Robinia pseudoaca-cia), has invaded Japanese black pine (Pinus thunbergii) forests located in Japan’s coastal plain and hill regions where gaps are formed in pine forests after nematode infestation. Nitrogen fixation by legumes acceler-ates N cycling in forest ecosystems. We studied temporal change in the annual tree-ring resolution N stable isotope composition (δ15N, a per mil deviation of δ15N/14N ratio, relative to atmospheric N2δ15N=0‰) at two natural locations of Japanese black pine forest with black locust that differed in the time since black locust establishment (Shohnai in north-east and Kita-Kyushu in southwest Japan). Analyzed tree-rings covered the period from 1990/1992 to 2009. N acquisition by Japanese black pine from black locust N input to the soil was evidenced by temporal shifting of N stable isotope composition on the annual pine tree rings. With pro-gressive development of the forest stand,δ15N values of earlier tree-ringsδ15N of -5‰) from black pine associated with black locust shifted to-wards values similar to those of black locustδ15N values nearly to-1‰), which suggests acquisition of N by N2 fixation (Shohnai site). In con-trast, in a forest where black locust had settled for two or three genera-tions, in a black pine stand (Kita-Kyushu site), longer periods of N en-richment in the soil were reflected in the elevated tree-ringδ15N values of newly established black pine trees. Based on tree-ringδ15N data from the Shohnai site, we determined that about 10 years after black locust establishment, soil N had already been enriched by black locust N, this, in turn, contributed to N fertilization of surrounding trees in mixed stands.
基金supported by the U.S.Department of Defense,through the Strategic Environmental Research and Development Program(SERDP)
文摘Accurate and efficient estimation of forest growth and live biomass is a critical element in assessing potential responses to forest management and environmental change. The objective of this study was to develop models to predict longleaf pine tree diameter at breast height (dbh) and merchantable stem volume (V) using data obtained from field measurements. We used longleaf pine tree data from 3,376 planted trees on 127 permanent plots located in the U.S. Gulf Coastal Plain region to fit equations to predict dbh and V as functions of tree height (H) and crown area (CA). Prediction of dbh as a function of H improved when CA was added as an additional independent variable. Similarly, predic- tions of V based on H improved when CA was included. Incorporation of additional stand variables such as age, site index, dominant height, and stand density were also evaluated but resulted in only small improvements in model performance. For model testing we used data from planted and naturally-regenerated trees located inside and outside the geographic area used for model fitting. Our results suggest that the models are a robust alternative for dbh and V estimations when H and CA are known on planted stands with potential for naturally-regenerated stands, across a wide range of ages. We discuss the importance of these models for use with metrics derived from remote sensing data.
文摘The thesis for the Doctorate consist of two parts. The first is to study on structure, dynamics and tree growth of natural Korean pine forest. The second is to research for tree architecture, growth and stand structure of artificial Korean pine (Pinus koraienstj) forcsts.The thesis comparcs the stand structure, process of regeneratio n, and various tree growth patterns between natural forests and artificial forests. Its purpose is to give a basis for forest management and silviculture. The study was carried out in Liangshui Experimental Forest Farm, which is located in the southern Xiaoxing’an Mountains.
文摘The article presents the first direct evidence of the influence of supernova flashes on the biosphere. Geochemistry and paleontology have not yet provided convincing data on the life response to disasters in the Milky Way Galaxy. This gap was eliminated through tree ring analysis of bristlecone pine from the Cordilleras responded to seven supernova outbursts in 185-1604 AD. The author used the superposed epoch method to process data at the 11 longest dendrochronologies, based on the results of measurement of annual growth of about 300 trees. The main finding is the growth depression in high-mountain population caused by supernova outbursts lasted for 20 - 30 years after the event. Moreover, in most cases, drastic growth reduction occurred one year prior to the event. In some cases, the annual tree ring increment exceeded the normal range many years after the event, and, consequently, it could be concluded that plant response was associated with the ozone layer depletion.
基金supported by National Key R&D Program of China(2017YFD0600601)
文摘Thinning of Korean pine (Pinus koraiensis Sieb. et Zucc.) is used to facilitate timber and cone production. The present study in Northeast China investigated the effects of thinning intensity on individual tree growth, temporal variation in cone yield, and seed quality in Korean pine plantation. In 2005, five thinning intensity levels (none, extreme, heavy, moderate and light) were set in 15 permanent plots in a 32-year-old Korean pine plantation at Mengjiagang Forest Farm, Jiamusi City, Heilongjiang Province. We recorded tree growth and seed cone production from 2013 to 2016, i.e., from 8 to 11 years after thinning. Except for height growth, thinning increased tree growth (diameter at breast height and crown size) and improved cone yield. The extreme thinning treatment (to 300 trees per hectare) resulted in the largest tree diameter, tree volume, crown size and 4-year cone production per tree. The highest cone yield per tree in the mast year (2014) was observed when stands were thinned to 500 trees per hectare (heavy thinning). Although the best cone and seed quality and the largest cone and seed mass per tree were recorded in the heavily thinned stand, no significant differences were found between heavy and moderate thinning stands (750 trees per hectare). At the stand level, the moderately thinned stand had the highest basal area, stock volume and seed cone production per stand. Our results suggest that thinning to 750 trees per hectare will improve timber and cone productivity in 40-year-old P. koraiensis stands.
文摘Ponderosa pine (Pinus ponderosa Laws.) has been planted widely in the Great Plains. Recommendations based on a 1968 study were to use material from south central South Dakota and north central Nebraska. A second test to further delineate seed sources (provenance/families) in this region was established in 1986. This paper reports results for survival, height, diameter, and D2H measurements in Kansas at 15 years. Results identify a wide range of suitable families within the Great Plains region.A majority of the tested sources performed well especially those from central Nebraska. Those sources from eastern Montana and western Nebraska performed poorly where environmental or geographic conditions were the poorest, thus verifying the original recommendations.
文摘为解决山地地形起伏大、无人机飞行高度高导致图像中尺度小且纹理模糊的松枯死木识别困难问题,该研究提出了一种在特征层级进行超分辨率重建的YOLOv5松枯死木识别算法。在YOLOv5网络中添加选择性核特征纹理迁移模块生成有细节纹理的高清检测特征图,自适应改变感受野的机制分配权重,将更多注意力集中在纹理细节,提升了小目标和模糊目标的识别精度。同时,使用前景背景平衡损失函数抑制背景噪声干扰,增加正样本的梯度贡献,改善正负样本分布不平衡问题。试验结果表明,改进后算法在交并比(intersection over union,IoU)阈值取0.5时的平均精度均值(mean average precision,mAP50)为92.7%,mAP50~95(以步长0.05从0.5到0.95间取IoU阈值下的平均mAP)为62.1%,APsmall(小目标平均精度值)为53.2%,相比于原算法mAP50提高了3.2个百分点,mAP50~95提升了8.3个百分点,APsmall提升了15.8个百分点。不同算法对比分析表明,该方法优于Faster R-CNN、YOLOv4、YOLOX、MT-YOLOv6,QueryDet、DDYOLOv5等深度学习算法,mAP50分别提高了16.7、15.3、2.5、2.8、12.3和1.2个百分点。改进后松枯死木识别算法具有较高精度,有效缓解了小目标与纹理模糊目标识别困难问题,为后续疫木清零提供技术支持。
基金This study was jointly supported by National Natural Science Foundation of China (30270282) and Guangdong Natural Science Foundation for Distinguished Young Scholars (003031)
文摘TREE submodel affiliated with TREEDYN was used to simulate biomass dynamics of Masson pine (Pinus massoniana) forest under different managements (including thinning, clear cutting, combining thinning with clear cutting). The purpose was to represent biomass dynamics involved in its development, which can provide scientific arguments for management of Masson pine forest. The results showed the scenario that 10% or 20% of biomass of the previous year was thinned every five years from 15 to 40 years made total biomass of pine forest increase slowly and it took more time to reach a mature community; If clear cutting and thinning were combined, the case C (clear cutting at 20 years of forest age, thinning 50% of remaining biomass at 30 years of forest age, and thinning 50% of remaining biomass again at 40 years of forest age) was the best scenario which can accelerate speed of development of Masson pine forest and gained better economic values.