L.C. JIANG

Northeast Forestry University

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N-Y Chang

Shidong Xin

Northeast Forestry University

Muhammad Khurram Shahzad

University of Lahore

Altaf Hussain

Islamia University of Bahawalpur

H-H Chiang

G Y ENZINGA

Northeast Forestry University

Cooperative Institutions

Northeast Forestry University

University of Lahore

Muhammad Nawaz Shareef University of Agriculture

Institute of Southern Punjab

Government of Punjab

Government of Pakistan

Islamia University of Bahawalpur

National University of Medical Sciences

Military Hospital

Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu

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EVALUATION OF REGION AND SUBREGION-BASED HEIGHTDIAMETER MODELS FOR DAHURIAN LARCH (LARIX GMELINII) IN DAXING’AN MOUNTAINS IN CHINA

Applied Ecology and Environmental Research (2019)

G Y ENZINGA L.C. JIANG

Using the felled tree data, subregions-based height-diameter models were developed for Dahurian larch (Larix gmelinii Rupr) in Daxing'an Mountains in China.Thirty frequently used nonlinear growth functions were fitted to individual tree height-diameter data.A total of 2411 for Dahurian larch trees were collected and measured.Parameter estimates and evaluation statistics were calculated using SAS PROC NLIN procedure for overall model, three regional models, and ten subregional models.The non-linear extra sum of squares method was used to assimilate the difference of the height-diameter relationships among different subregions.The results indicate that the Chapman-Richards growth function show the best for fitting tree height-diameter relationships at regional and subregional levels with a root mean square error RMSE = 2.193 and coefficient determination R 2 = 0.8221.It was revealed that, Dahurian larch height-diameter relationships showed the several differences among these regions and subregions (P < 0.0001) when overall, regional and subregional model was applied to predict tree height separately in each region and subregion.Among the 45 pairs of subregions, only four subregion pairs (e.g., XL versus SBZ, XL versus HJY, SBZ versus HJY, and XL versus JGDQ) showed the nonsignificant difference F-value (P > 0.05) and the data from those subregions were combined and applied to others subregions; all comparisons show the difference.The tree height-diameter relationships of Dahurian larch are significantly different among the geographic regions in Daxing'an Mountains, depending on local climatic, soil, and ecological conditions.

Larix gmelinii

Tree (set theory)

10.15666/aeer/1706_1356713591

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RESILIENT MODULUS OF GRANULAR SOILS WITH FINES CONTENTS. FINAL REPORT

N-Y Chang H-H Chiang L.C. JIANG

This study examined the relationship of resilient modulus with the stabilometer R-values, and with the index properties of Colorado soils. A total of 39 resilient modulus tests were conducted, 20 in this test program and 19 in an earlier test program. Soil types ranged from A-1-a to A-7-6 with varying amounts of fines. Regression analyses were performed to formulate the functional relationship using the least square fit. Two regression equations were formulated to relate resilient modulus to R-value (one linear and one nonlinear), and four linear regression equations to relate resilient modulus to percent fines content, plasticity index, uniformity coefficient, and mean grain size. In general, the values of the Correlation coefficients are small and care should be taken when using these equations, particularly for granular soil samples with less than 30% of fines. It is recommended to abandon the effort to formulate a relationship between resilient modulus and R-value because of the inability of R-value in reflecting dynamic behavior of soils.

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COMPATIBLE STEM VOLUME AND TAPER EQUATIONS FOR FIVE MAJOR TREE SPECIES IN NORTHEAST CHINA

Applied Ecology and Environmental Research (2020)

Altaf Hussain Muhammad Khurram Shahzad Shidong Xin L.C. JIANG

Compatible segmented taper and volume equations were developed for Dahurian larch, Korean spruce, Manchurian fir, planted Dahurian larch and Mongolian pine in northeast China.The model form developed by Max and Burkhart (1976) was fitted to the data of 720 sample trees.The data was randomly split into two sets for each species: 80% of total data was used for model fitting, and 20% of total data was reserved for model validation.The proposed equation provided good results for the whole tree and different stem sections.Mean prediction errors for diameter and volume were less than 1.9 cm and 0.005 m 3 , respectively.The recommended model provided adequate diameter and merchantable volume estimates against ten relative height classes, examined for each species.Additionally, the model's estimates were superior to the existing volume tables for these commercial species, particularly for Korean spruce, Manchurian fir, and planted Dahurian larch.

Tree (set theory)

10.15666/aeer/1805_62956308

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