FSOs forest simulation optimization model learning notes

Forest simulation optimization model (forest simulation and optimization system,FSOS)

FSOS Simulated annealing algorithm is used to arrange forest management , Control multiple resources through parameter coordination , Fully consider the complex forest environment and stand growth , Realize multi-objective and long-term sustainable forest management .

Using forest simulation optimization model (FSOS) Analyze the forest

2095-0756(2020)05-0833-08

summary ：

This paper compares traditional methods with FSOS The reasonable annual cutting amount is calculated . 

data ：

1. Tree height and age data of tree species

2. Including stand dynamics and landscape level “ Non timber resources ” indicators

3. The maximum annual average growth of the stock (MAI)、 The age of the forest when the volume reaches the maximum annual average growth (TMax)

When calculating the cutting volume , The model can fully consider the age group structure of forest 、 Tree species composition and stand growth evolution law , Find the optimal solution by simulated annealing algorithm .

①57 Survey factors , Including the sub class number 、 Small class area 、 Tree species composition 、 Average age 、 Average tree height 、 Mean DBH 、 Storage capacity 、 Number of plants per hectare 、 Forest category 、 origin 、 Protection level 、 Age group 、 Land type 、 slope 、 Slope direction, etc .

② Compare the traditional formula method with the actual growth curve

③FSOS The basic parameters of the model include stand dynamics and landscape level “ Non timber resources ” indicators . Stand dynamic parameters include   The maximum annual average growth of the stock (MAI)、 The age of the forest when the volume reaches the maximum annual average growth (TMax) And the constant controlling the volume growth curve (MValue) , Input the data of each tree species based on the second-class data MAI and TMax,MValue Value taking 3, be based on Richards equation , With this 3 Nonlinear regression analysis is carried out with parameters as initial values , Generate the growth curve of tree species .

Stand and growth curve   

The stand and its growth curve are based on the small class attribute in the second class survey data , adopt FSOS The stand modules in the model are fitted to generate . Tree growth curve is a basic parameter to quantitatively measure stand dynamics , stay FSOS In the model , The growth attributes of different tree species are the basic input parameters of the model .FSOS The model is based on the composition of tree species in the small class 、 Storage capacity 、 DBH 、 The attribute value of tree height fits the accumulation of tree species 、 Tree height and DBH growth curve . The dominant tree species and site level are used as fitting parameters , Based on the attribute values of small classes, the scatter diagrams of various tree species at different site levels are generated , Use Richards The equation fits the growth curve of the corresponding tree species and gives the corresponding determination coefficient R2, To evaluate the fitting effect . According to the similar growth characteristics of tree species , Combine tree species with less data or poor data quality , Re fitting the growth curve to improve the fitting effect of tree growth curve .FSOS The model creates the stand according to the following rules ： The same stand must have the same tree species 、 Scale and site level ; When the proportion of dominant tree species is greater than 70% when , Change the stand into pure forest ; When the stand has the same species and proportion , And the total proportion of these tree species is greater than 80% when , Combined stands ; When the proportion difference of the same tree species is less than 20% when , Combined stands . Use corresponding Tree species growth curve according to the tree species composition and proportion of each stand, the growth curve of the stand is proposed , It can be used to predict the future growth and evolution of the stand .

 

FSOS The model has map function , Be able to combine the small class with the topographic map , Accurately locate the cutting distribution of each cycle to specific small class plots , And show it on the map , Ensure the accuracy of the application , It can direct the forest operation , It is convenient for forest management .

Scheme settings      according to 《 Summary of the research on forestry strategy for sustainable development in China 》 The young forest of forest resources proposed in 、 Middle aged forest 、 Near mature forest 、 Mature forest 、 Proportion of over mature forest area 2∶1∶1∶2∶1, Set the desired state , Mature forest 、 The area of over mature forest accounts for 42.86% It is an ideal age group distribution [15]. Give priority to the control of mature forests 、 Over mature forest area , Increase stand value , Create a good forest structure and landscape pattern . Create the main cutting scheme of timber forest in the scheme module , With 5 a by 1 Planning units , Altogether 10 Job cycles , Study the future 50 a Forest farm management and forest cutting . Select the general timber forest as the management cutting object , The operation scheme has been optimized and iterated for tens of thousands of times , Generate the optimal solution .