Valuation Of Forest Resources Monitoring And Forest Management Effect Of Experimental Center Of Tropical Forestry

Forest resources monitoring of forest management unit (FMU) enable FMU master thecurrent resources status and dynamics, evalute the effect of management measures and forecastchanging trend of forest resources, providing a basis for operating decision, as well as forestresources information for higher level FMU. Accurately understand the status of forestresources to formulate pointed forest management measures. Forest management is the eternaltheme in forestry, and has great significance in improving china forestry, which transform thetraditional forestry to modern forestry. Close-to-nature management is one forest managementsystem based on the stability of forest ecosystem biodiversity，multi-function and buffercapacity analysis, with the forest life cycle as the design unit of time, the tag and selectivecutting of target trees and natural regeneration as the main technical characteristics, permanentforest cover, multi-fuctional management and multi-quality products as the targets. Therefore,monitoring of forest resource and evaluation of forest management effect of ExperimentalCenter of Tropical Forestry (ECTF) were conducted based on monitoring plots of systematicalsampling at FMU level, typical plots under close-to-nature forest management and other plotsinvestigation.Criteria system of monitoring and evaluation of forest resources of ECTF was developed,which composed of8categories and25observation indices within the framework ofinternational uniform evaluation index of forest resource. This changed the current situationthat the evaluation index system and forest monitoring region are too large. Meanwhile the dataacquisition was proposed, the monitoring system at FMU level was divided into general plotsfor common observation indices and intensive plots for special indices, and all observationindices were divided into short cycle and long period investigation intensity, which improvedthe survey efficiency and satisfied the data demand for evaluation. Parameters calculation and analysis method of individual tree、forest and forest management unit was systematicallyproposed.Close-to-nature forest management (CNFM) had significantly influence on promotingthe growth of trees in upper and lower strata relative to rotation management (RM), but not fortrees in middle strata. CNFM effectively improved the growth of retained trees (target tree andcommon tree) to cultivate large timber, as well as increased the ingrowth volume and volumeperiodic annual increment (PAI), however the differences in ingrowth volume and PAI betweenrotation management and non-management stand were not statistically significant. CNFMcomparing with rotation management significantly promoted the growth of masson pine andbroadleaf species, therefore CNFM was superrior to rotation managment concerning improvingforest productivity.The species diversity and evenness in CNFM forest were higher than that in RM forest.the differences between them were statistically significant, broadleaf tree species replantedunderstory in CNFM forest had protective effect on natural regeneration seedlings, increasedstand biodiversity and improved growth condition, therefore facilitated the growth ofunderstory trees to enter the main story. In addition, understory replantation could speedsuccession process up to reach target forest form-multi-strata, uneven age and mingled forest.The measure II (retained450-450trees/hm2in which target trees150-75trees/hm2) ofthree treatments was most conducive to growth of broadleaf trees replanted understory, had thehighest survival rate, ingrowth volume and dbh range of broadleaf species. Therefore measureII was the best operation of masson pine close-to-nature transformation oriented by target tree.In addition, Castanopsis fissa and Manglietia glance grew best, secondly Castanopsis hystrixand Michelia hedyosperma among broadleaf species replanted understorey, as for naturalregeneration species, Styrax benzoin, Schefflera arboricola and Quercus acutissima grewbetter than others.Forest succession stage is the foundation of individual tree management based on targettree, and is easy to define and describe operation measures. Pinus massoniana forest under management were divided five forest stages, i.e. forest establishment stage, competitiondifferentiation stage, selection stage, close-to-nature stage and naturalness permanent foreststage, were presented based on previous researches. Stepwise discriminant (Wilks’Lambda)was used to select important indices among initial13stand indices. Age, average dbh ofdominate tree species, ratio of tree volume to total volume, stand basal area, and dbh variablecoefficient were selected to classify forest stage. Fisher discriminant function and Bayesdiscriminant function were established referring to the five indices mentioned above, theclassification results were94%of training samples correctly classified,89%of verificationsamples correctly classified, and ratio of tree volume to total volume is the best index toidentify forest stage.The forest land area is17048hectare with forest coverage74.4%based on the data ofsystematic sample at FMU level in2013. The Pinus massoniana forest area decreased, oncontrary, that of broadleaf-conifer mixed forest and broadleaf forest were increased. The forestvolume annual increment was11.9m3/hm2/yr with85.3%estimated accuracy from2011to2013year of ECTF. The volume increments of forest types of eucalyptus, broadleaf-conifermixed forest, masson pine were19.1m3/hm2/yr,12.6m3/hm2/yr,12.1m3/hm2/yr, respectively.Broadleaf specise which were in middle and low strata of broadleaf-conifer mixed forest,orwere young and middle aged trees in broadleaf forest were key management objects, neededtending thinning to facilitate their growth.The dbh increment of individual tree of Pinus massoniana was positive correlation withbeginning dbh, site index, the ratio of dbh of object tree to average dbh of stand, the sumbasal area of trees with larger dbh than object tree, and was negative correlation with slope,mingling, basal are of stand, and the differences in dbh growth among different slop classesand site index were statistical significant. For that of broadleaf species including Mytilarialaosensis, Manglietia glanca, Quercus griffithii, Michelia macelurei, Betula alnoides waspositive correlation with beginning dbh and the ratio of dbh of object tree to average dbh ofstand, was negative correlation with the sine of aspect and basal area of stand. the dbh growth of tree in southeast, south aspect was greatest, that in east, north, southwest was second, thennortheast and northwest aspect, and the differences among these three blocks of aspect werestatistically significant.