scholarly journals A Linkage among Tree Diameter, Height, Crown Base Height, and Crown Width 4-Variate Distribution and Their Growth Models: A 4-Variate Diffusion Process Approach

Forests ◽  
2017 ◽  
Vol 8 (12) ◽  
pp. 479 ◽  
Author(s):  
Petras Rupšys ◽  
Edmundas Petrauskas
Keyword(s):  
Diffusion Process ◽  
Growth Models ◽  
Process Approach ◽  
Tree Diameter ◽  
Crown Width ◽  
Crown Base Height

scholarly journals Individual-Tree Diameter Growth Models for Mixed Nothofagus Second Growth Forests in Southern Chile

Forests ◽  
2017 ◽  
Vol 8 (12) ◽  
pp. 506 ◽  
Author(s):  
Paulo Moreno ◽  
Sebastian Palmas ◽  
Francisco Escobedo ◽  
Wendell Cropper ◽  
Salvador Gezan
Keyword(s):  
Growth Models ◽  
Diameter Growth ◽  
Southern Chile ◽  
Individual Tree ◽  
Tree Diameter ◽  
Second Growth ◽  
Diameter Growth Models

An interface diffusion process approach for the fabrication of MgB2wire

2006 ◽  
Vol 19 (6) ◽  
pp. L17-L20 ◽  
Author(s):  
K Togano ◽  
T Nakane ◽  
H Fujii ◽  
H Takeya ◽  
H Kumakura
Keyword(s):  
Diffusion Process ◽  
Process Approach ◽  
Interface Diffusion

scholarly journals Individual Tree Diameter Growth Models of Larch–Spruce–Fir Mixed Forests Based on Machine Learning Algorithms

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 187 ◽  
Author(s):  
Qiangxin Ou ◽  
Xiangdong Lei ◽  
Chenchen Shen
Keyword(s):  
Machine Learning ◽  
Tree Growth ◽  
Growth Models ◽  
Tree Size ◽  
Diameter Growth ◽  
Individual Tree ◽  
Mixed Forests ◽  
Tree Diameter ◽  
Individual Tree Growth ◽  
The Individual

Individual tree growth models are flexible and commonly used to represent growth dynamics for heterogeneous and structurally complex uneven-aged stands. Besides traditional statistical models, the rapid development of nonparametric and nonlinear machine learning methods, such as random forest (RF), boosted regression tree (BRT), cubist (Cubist) and multivariate adaptive regression splines (MARS), provides a new way for predicting individual tree growth. However, the application of these approaches to individual tree growth modelling is still limited and short of a comparison of their performance. The objectives of this study were to compare and evaluate the performance of the RF, BRT, Cubist and MARS models for modelling the individual tree diameter growth based on tree size, competition, site condition and climate factors for larch–spruce–fir mixed forests in northeast China. Totally, 16,619 observations from long-term sample plots were used. Based on tenfold cross-validation, we found that the RF, BRT and Cubist models had a distinct advantage over the MARS model in predicting individual tree diameter growth. The Cubist model ranked the highest in terms of model performance (RMSEcv [0.1351 cm], MAEcv [0.0972 cm] and R2cv [0.5734]), followed by BRT and RF models, whereas the MARS ranked the lowest (RMSEcv [0.1462 cm], MAEcv [0.1086 cm] and R2cv [0.4993]). Relative importance of predictors determined from the RF and BRT models demonstrated that the competition and tree size were the main drivers to diameter growth, and climate had limited capacity in explaining the variation in tree diameter growth at local scale. In general, the RF, BRT and Cubist models are effective and powerful modelling methods for predicting the individual tree diameter growth.

Tunneling time based on the quantum diffusion process approach in multichannel and optical potential cases

Pramana ◽  
1998 ◽  
Vol 51 (5) ◽  
pp. 603-614
Author(s):  
Ichiro Ohba ◽  
Kentaro Imafuku ◽  
Yoshiya Yamanaka
Keyword(s):  
Diffusion Process ◽  
Optical Potential ◽  
Process Approach ◽  
Tunneling Time ◽  
Quantum Diffusion

Effects of inelastic scattering on tunneling time based on the generalized diffusion process approach

1997 ◽  
Vol 56 (2) ◽  
pp. 1142-1153 ◽  
Author(s):  
Kentaro Imafuku ◽  
Ichiro Ohba ◽  
Yoshiya Yamanaka
Keyword(s):  
Diffusion Process ◽  
Inelastic Scattering ◽  
Process Approach ◽  
Tunneling Time

scholarly journals Models for diameter and height growth of Scots pine, Norway spruce and pubescent birch in drained peatland sites in Finland

Silva Fennica ◽  
2018 ◽  
Vol 52 (5) ◽  
Author(s):  
Jaakko Repola ◽  
Hannu Hökkä ◽  
Hannu Salminen
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Growth Models ◽  
Mineral Soil ◽  
Height Growth ◽  
Growth Patterns ◽  
Repeated Measurements ◽  
Site Quality ◽  
Individual Tree ◽  
Tree Diameter

The aim of this study was to develop individual-tree diameter and height growth models for Scots pine, Norway spruce, and pubescent birch growing in drained peatlands in Finland. Trees growing in peatland sites have growth patterns that deviate from that of trees growing in mineral soil sites. Five-year growth was explained by tree diameter, different tree and stand level competition measures, management operations and site characteristics. The drainage status of the site was influencing growth directly or in interaction with other variables. Site quality had a direct impact but was also commonly related to current site drainage status (need for ditch maintenance). Recent thinning increased growth of all species and former PK fertilization increased growth of pine and birch. Temperature sum was a significant predictor in all models and altitude for spruce and birch. The data were a subsample of the 7th National Forest Inventory (NFI) sample plots representing northern and southern Finland and followed by repeated measurements for 15–20 yrs. Growth levels predicted by the models were calibrated using NFI11 data to remove bias originating from the sample of the modelling data. The mixed linear models technique was used in model estimation. The models will be incorporated into the MOTTI stand simulator to replace the current peatlands growth models.

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