We studied relationships between stand structure and stand stability according to thinning intensity in an afforested oriental beech stand. Various thinning intensities were applied in sample stands. We sampled eight ...We studied relationships between stand structure and stand stability according to thinning intensity in an afforested oriental beech stand. Various thinning intensities were applied in sample stands. We sampled eight plots in stands that were lightly thinned, eight plots in heavily thinned stands and eight plots in unthinned stands as a control. Height and diameter distributions of the stands were measured to assess stand structure. We quantified individual tree stability and collective stability. Heavy thinning during the first thinning operation damaged the storied structure of the stand in thicket stage and affected collective structuring ability. While most control plots had multi-storied stands, after light and heavy thinning two-storied structure became more common.Large gaps occurred in the canopy after heavy thinning. On average, nine tree collectives were formed per sampling plot in the untreated stand, seven collectives after thinning in 2008 and four collectives after thinning in 2009. Stable trees accounted for 17 % of trees in control plots, 24 % in lightly thinned plots, and 15 % in heavily thinned plots. Collective stability values were 83 % in control plots, 82 % in lightly thinned plots and 36 % in heavily thinned plots. We conclude that it is necessary to retain collective structuring capacity during thinning operations for sustaining stand stability.展开更多
The competition-density (C-D) effects for mean mass for tree, stem, branch and leaf were analyzed in Acacia auriculiformis stands. Mean tree mass-density and mean organ mass-density were well explained by the C-D equa...The competition-density (C-D) effects for mean mass for tree, stem, branch and leaf were analyzed in Acacia auriculiformis stands. Mean tree mass-density and mean organ mass-density were well explained by the C-D equation of tree and the C-D equation of tree organ, respectively. An equation describing the relationship between mean leaf area u and density was formulated that fit the u-data well. The relationship between mean tree mass w and the ratio of each organ to mean tree mass (wo/ w) was examined. With increasing w, the stem mass ratio wS/w increased, whereas the branch mass ratio wB/w and the leaf mass ratio wL/w decreased. The yield difference between the lowest-density stand and the high-density stand became greater with stand growth. However, the yield of the mid-density stand was slightly lower than the yield of the high-density stand during the experimental period. To produce the most desirable combination of demanding individual-tree size and relative high stem yield, the mid-density is recommended as proper planting density for future management of A. auriculiformis stands.展开更多
Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura. Overall 10,957 individual trees belonging ...Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura. Overall 10,957 individual trees belonging to 46 family, 103 genera and 144 species were counted at ≥30 cm DBH (diameter at breast height) using 28 permanent belt transects with a size of 1 ha (10 m × 1000 m). Four different tree communities were identified. The primary forests was dominated by Shorea robusta (mean density 464.77 trees.ha^-1, 105 species) and Schima wallichii (336.25 trees.ha^-1, 82 species), while the secondary forests was dominated by Tectona grandis (333.88 trees.ha^-1, 105 species) and Hevea brasiliensis (299.67 trees.ha^-1, 82 species). Overall mean basal area in this study was 18.01m2.ha^-1; the maximum value was recorded in primary Shorea forest (26.21 m2.ha^-1). Mean density and diversity indices were differed significantly within four different communities. No significant differences were observed in number of species, genera, family and tree basal cover area. Significant relationships were found between the species richness and different tree population groups across the communities. Results revealed that species diversity and density were increased in those forests due to past disturbances which resulted in slow accumu- lation of native oligarchic small tree species. Seventeen species were recorded with 〈2 individuals of which Saraca asoka (Roxb.) de Wilde and Entada phaseoloides (L.) Men'. etc. extensively used in local ethnomedicinal formulations. The present S. robusta Gaertn dominated forest was recorded richer (105 species) than other reported studies. Moraceae was found more speciose family instead of Papilionaceae and Euphorbiaceae than other Indian moist deciduous forests. Seasonal phenological gap in such moist deciduous forests influenced the population of Trachypithecus pileatus and capped langur. The analysis of FIV suggested a slow trend of shifting the population of Lamiaceae group by Moraceae species in secondary T. grandis L. dominated community.展开更多
AIM: To characterize and compare our current series of patients to prior reports in order to identify any changes in the incidence of neurological injury related to hunting accidents in Rochester, New York.METHODS: Al...AIM: To characterize and compare our current series of patients to prior reports in order to identify any changes in the incidence of neurological injury related to hunting accidents in Rochester, New York.METHODS: All tree stand-related injuries referred to our regional trauma center from September 2003 through November 2011 were reviewed. Information was obtained from the hospital's trauma registry and medical records were retrospectively reviewed for data pertaining to the injuries.RESULTS: Fifty-four patients were identified. Ninetysix percent of patients were male with a mean age of 47.9 years(range 15-69). The mean Injury Severity Score was 12.53 ± 1.17(range 2-34). The average height of fall was 18.2 feet(range 4-40 feet). All patients fell to the ground with the exception of one who landed on rocks, and many hit the tree or branches on the way down. A reason for the fall was documented in only 13 patients, and included tree stand construction(3), loss of balance(3), falling asleep(3), structural failure(2), safety harness breakage(3) or lightheadedness(1). The most common injuries were spinal fractures(54%), most commonly in the cervical spine(69%), followed by the thoracic(38%) and lumbar(21%) spine. Eight patients required operative repair. Head injuries occurred in 22%. Other systemic injuries include rib/clavicular fractures(47%), pelvic fractures(11%), solid organ injury(23%), and pneumothorax or hemothorax(19%). No patient deaths were reported. The average hospital length of stay was 6.56 ± 1.07 d. Most patients were discharged home without(72%) or with(11%) services and 17% required rehabilitation. CONCLUSION: Falls from hunting tree stands are still common, with a high rate of neurological injury. Compared to a decade ago we have made no progress in preventing these neurological injuries, despite an increase in safety advances. Neurosurgeons must continue to advocate for increased safety awareness and participate in leadership roles to improve outcomes for hunters.展开更多
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
基金supported by Karadeniz Technical University Research Fund,Project number 2010.113.001.11
文摘We studied relationships between stand structure and stand stability according to thinning intensity in an afforested oriental beech stand. Various thinning intensities were applied in sample stands. We sampled eight plots in stands that were lightly thinned, eight plots in heavily thinned stands and eight plots in unthinned stands as a control. Height and diameter distributions of the stands were measured to assess stand structure. We quantified individual tree stability and collective stability. Heavy thinning during the first thinning operation damaged the storied structure of the stand in thicket stage and affected collective structuring ability. While most control plots had multi-storied stands, after light and heavy thinning two-storied structure became more common.Large gaps occurred in the canopy after heavy thinning. On average, nine tree collectives were formed per sampling plot in the untreated stand, seven collectives after thinning in 2008 and four collectives after thinning in 2009. Stable trees accounted for 17 % of trees in control plots, 24 % in lightly thinned plots, and 15 % in heavily thinned plots. Collective stability values were 83 % in control plots, 82 % in lightly thinned plots and 36 % in heavily thinned plots. We conclude that it is necessary to retain collective structuring capacity during thinning operations for sustaining stand stability.
基金supported by the Forestry Technology Popularization Demonstration Project of the Central Government of China(No.[2015]GDTK-07)
文摘The competition-density (C-D) effects for mean mass for tree, stem, branch and leaf were analyzed in Acacia auriculiformis stands. Mean tree mass-density and mean organ mass-density were well explained by the C-D equation of tree and the C-D equation of tree organ, respectively. An equation describing the relationship between mean leaf area u and density was formulated that fit the u-data well. The relationship between mean tree mass w and the ratio of each organ to mean tree mass (wo/ w) was examined. With increasing w, the stem mass ratio wS/w increased, whereas the branch mass ratio wB/w and the leaf mass ratio wL/w decreased. The yield difference between the lowest-density stand and the high-density stand became greater with stand growth. However, the yield of the mid-density stand was slightly lower than the yield of the high-density stand during the experimental period. To produce the most desirable combination of demanding individual-tree size and relative high stem yield, the mid-density is recommended as proper planting density for future management of A. auriculiformis stands.
基金supported by DBT Network Project (BT/PR7928/NDB/52/9/2006)Department of Biotechnology(DBT),Govt. of India
文摘Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura. Overall 10,957 individual trees belonging to 46 family, 103 genera and 144 species were counted at ≥30 cm DBH (diameter at breast height) using 28 permanent belt transects with a size of 1 ha (10 m × 1000 m). Four different tree communities were identified. The primary forests was dominated by Shorea robusta (mean density 464.77 trees.ha^-1, 105 species) and Schima wallichii (336.25 trees.ha^-1, 82 species), while the secondary forests was dominated by Tectona grandis (333.88 trees.ha^-1, 105 species) and Hevea brasiliensis (299.67 trees.ha^-1, 82 species). Overall mean basal area in this study was 18.01m2.ha^-1; the maximum value was recorded in primary Shorea forest (26.21 m2.ha^-1). Mean density and diversity indices were differed significantly within four different communities. No significant differences were observed in number of species, genera, family and tree basal cover area. Significant relationships were found between the species richness and different tree population groups across the communities. Results revealed that species diversity and density were increased in those forests due to past disturbances which resulted in slow accumu- lation of native oligarchic small tree species. Seventeen species were recorded with 〈2 individuals of which Saraca asoka (Roxb.) de Wilde and Entada phaseoloides (L.) Men'. etc. extensively used in local ethnomedicinal formulations. The present S. robusta Gaertn dominated forest was recorded richer (105 species) than other reported studies. Moraceae was found more speciose family instead of Papilionaceae and Euphorbiaceae than other Indian moist deciduous forests. Seasonal phenological gap in such moist deciduous forests influenced the population of Trachypithecus pileatus and capped langur. The analysis of FIV suggested a slow trend of shifting the population of Lamiaceae group by Moraceae species in secondary T. grandis L. dominated community.
文摘AIM: To characterize and compare our current series of patients to prior reports in order to identify any changes in the incidence of neurological injury related to hunting accidents in Rochester, New York.METHODS: All tree stand-related injuries referred to our regional trauma center from September 2003 through November 2011 were reviewed. Information was obtained from the hospital's trauma registry and medical records were retrospectively reviewed for data pertaining to the injuries.RESULTS: Fifty-four patients were identified. Ninetysix percent of patients were male with a mean age of 47.9 years(range 15-69). The mean Injury Severity Score was 12.53 ± 1.17(range 2-34). The average height of fall was 18.2 feet(range 4-40 feet). All patients fell to the ground with the exception of one who landed on rocks, and many hit the tree or branches on the way down. A reason for the fall was documented in only 13 patients, and included tree stand construction(3), loss of balance(3), falling asleep(3), structural failure(2), safety harness breakage(3) or lightheadedness(1). The most common injuries were spinal fractures(54%), most commonly in the cervical spine(69%), followed by the thoracic(38%) and lumbar(21%) spine. Eight patients required operative repair. Head injuries occurred in 22%. Other systemic injuries include rib/clavicular fractures(47%), pelvic fractures(11%), solid organ injury(23%), and pneumothorax or hemothorax(19%). No patient deaths were reported. The average hospital length of stay was 6.56 ± 1.07 d. Most patients were discharged home without(72%) or with(11%) services and 17% required rehabilitation. CONCLUSION: Falls from hunting tree stands are still common, with a high rate of neurological injury. Compared to a decade ago we have made no progress in preventing these neurological injuries, despite an increase in safety advances. Neurosurgeons must continue to advocate for increased safety awareness and participate in leadership roles to improve outcomes for hunters.
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.