Investigation on canopy cover height and density differentiations in the managed and unmanaged forest stands using Lidar data (Case study: Shastkalateh forest, Gorgan) |
Paper ID : 1001-SMPR-FULL |
Authors: |
شعبان شتایی جویباری *1, جهانگیر محمدی2 1گرگان- میدان بسیج- پردیس دانشگاه علوم کشاورزی و منابع طبیعی گرگان- دانشکده علوم جنگل 2عضو هیئت علمی گروه جنگلداری |
Abstract: |
The Hyrcanian original and natural forests in the northern Iran are almost high dense canopy cover and multi-layers vertical structure with high variance. Forest management plans are certificated approaches for applying forest managing and silviculture treatments programs to optimal forest management and keeping the forest stand natural composite and structure. The forest managers are interesting to aware of forest composite and structure situation before and after silvicultural and management treatments. In order to investigate on stand differences made by management plan, comparing of these stands with unmanaged stands as a nature of forests is necessary. In other hands, the field way to obtain these information is time and cost consuming. Using of other ways such as remote sensing sources is an alternative way. Aerial laser scanner instruments can provide suitable 3D information to map the horizontal and vertical characteristics of forest structures. In this study, different of canopy height and canopy cover variances between managed and unmanaged forest stands were investigated in Dr. Bahramnia forest in districts-based as well as in two dominant forest types using Lidar data. The in-situ information was gathered from 308 circular plots with 0.1 ha area by a random systematic sampling design and 150 * 200 meters dimension in managed and unmanaged districts. The plots were accurately positioned using a differential GPS and post processing kinematic method. The lidar point cloud data with approximately 4-5 pulses per square meters were taken from study area and then classified in first, last and other pulses using RiProcess software. in addition, all outliers with exceeder than 50 meters in last, first and other pulses were removed using Terrascan software. An accurate bare earth model (DEM) with spatial resolution of 1m was create using last pulses by Kraus and Pfeiffer algorithm. also, using the first pulses, the digital surface model (DSM) was generated in Fusion software. The plot-based height statistics metrics and canopy cover characteristics information were generated using DTM and DSM models. General statistical measures and significant analyses were done by independent T test between two districts as well as between two same dominant forest types (i.e. Carpinus-Parrotia and Parrotia-Carpinus) in the study area. Results showed that there are no significant differences in 95 percent confidence level between canopy cover mean in two districts and in two forest types. Result of statistically analysis on height characteristics showed that there are a decreasing the forest height and its variance in the managed forest in compared to unmanaged stands. In addition, there is a significant difference between maximum, range, and mean heights of two stands in 99 percent confidence level. However, there is no significant difference between standard deviation and canopy height variance of district I (managed stands) and district II. These results show that accomplished management treatments and cuttings could lead to reducing of height variances and converting multi-layers stands to two or single layers. Results are also showed that the canopy cover densities in the district I as the managed forest stands is changing from high dense cover to dense cover. although there are not serious problems and different between managed and unmanaged forest stands, however, theses valuable information should be used for re-decision making on forest treatments and management activities. |
Keywords: |
Canopy height, Canopy density, Lidar, Managed forest, Unmanaged forest, Dr. Bahramnia forest plan of Gorgan |
Status : Paper Accepted (Oral Presentation) |