• 대한원격탐사학회지
• /
• 제27권6호
• /
• pp.703-715
• /
• 2011

Forests have been considered one of the most important ecosystems on the earth, affecting the lives and environment. The sustainable forest management requires accurate and timely information of forest and tree parameters. Appropriately interpreted remotely sensed imagery can provide quantitative data for deriving forest information temporally and spatially. Especially, analysis of individual tree detection and crown delineation is significant issue, because individual trees are basic units for forest management. Individual trees in aerial imagery have reflectance characteristics according to tree species, crown shape and hierarchical status. This study suggested a method that identified individual trees and delineated crown boundaries through adopting gradient method algorithm to amplified greenness data using red and green band of aerial imagery. The amplification of specific band value improved possibility of detecting individual trees, and gradient method algorithm was performed to apply to identify individual tree tops. Additionally, tree crown boundaries were explored using spectral intensity pattern created by geometric characteristic of tree crown shape. Finally, accuracy of result derived from this method was evaluated by comparing with the reference data about individual tree location, number and crown boundary acquired by visual interpretation. The accuracy ($\hat{K}$) of suggested method to identify individual trees was 0.89 and adequate window size for delineating crown boundaries was $19{\times}19$ window size (maximum crown size: 9.4m) with accuracy ($\hat{K}$) at 0.80.

• 한국산림과학회지
• /
• 제98권2호
• /
• pp.178-182
• /
• 2009

A new mixed-effects model was developed that predicts individual-tree total height for Pinus densiflora trees in Gangwon province as a function of individual-tree diameter (cm). The mixed-effects model contains two random-effects parameters. Maximum likelihood estimation was used to fit the model to 560 height-diameter observations of individual trees measured throughout Gwangwon province in 2007 as part of the National Forest Inventory Program in Korea. The new model is an improvement over fixed-effects models because it can be calibrated to a local area, such as an inventory plot or individual stand. The new model also appears to be an improvement over the Forest Resources Evaluation and Prediction Program for the ten calibration trees used in this study. An example is provided that describes how to estimate the random-effects parameters using ten calibration trees.

• 한국산림과학회지
• /
• 제97권5호
• /
• pp.501-507
• /
• 2008

The data of crown width with 4 directions, DBH, tree height, and coordinate for sample trees were collected from 30 permanent sample plots in secondary fore st of the Maoershan Experimental Forestry Farm, Northeast China. In this paper, the competition of individual trees in stand were discussed for secondary forest by using iterative Hegyi competition index and crown overlap index that represented the competitive and cooperative interactions among neighboring trees. Active competitors of subject tree in the competition zone were selected to calculate the iterative competition index. Using the results of crown classification based on the equal crown projection area, a new distance dependent competition index called crown overlap index (COI) was developed for secondary forest. The COI performed well in describing the crown competition rather than crown competition factor (CCF). The individual-based competition index discussed in this paper will provide more precise for developing individual tree growth models for secondary forest and it can also use to adjust the stand structure for spatial optimal management.

• 한국산림과학회지
• /
• 제71권1호
• /
• pp.40-44
• /
• 1985

본(本) 조사(調査)는 낙엽송(落葉松) 인공성림지(人工成林地)에서, 간벌(間伐)이 가(加)해진 임분(林分)과 가(加)해지지 않은 고정표본구(固定標本區)에서 임목(林木) 개체간(個體間)의 생장상관(生長相關)을 가지고 개체간(個體間)의 경쟁효과(競爭効果)를 알아 보기 위하여 실시(實施)하였다. 1) 조사(調査)는 흉고부위(胸高部位)에서 increment borer에 의하여 채취(採取)된 core에서 연년생장(連年生長)과 총생장(總生長)을 조사(調査)하고 이에 의하여 인접임목개체간(隣接林木個體間)의 상관관계(相關關係)를 계산(計算)해서 확인(確認)하였다. 2) 경쟁효과(競爭効果)의 추정방법(推定方法)은 (1)$^rA_iA_j$, (2)$^rA_i\sum\limits_{k=1}^{n}A_k$, (3)$^rA_i\sum\limits_{k=1}^{n}A_k/R{_k}^2$을 사용(使用)했으며 이 방법(方法) 중(中)에서 $^rA-A_j$가 실용적(實用的)이었다. 3) 상관관계(相關關係)에 사용(使用)된 생장량(生長量)은 반경(半徑)과 단면적(斷面績)의 총생장량(總生長量)을 이용하였으며, 이들 생장량(生長量)의 상관(相關)에서 경쟁(競爭)이 일어나는 정도(程度)를 추정(推定)했다. 4) 식재후(植栽後) 10년까지는 상호경쟁(相互競爭)이 일어나지 않고 인접개체간(隣接個體間)의 상관(相關)은 높은 정(正)의 상관(相關)을 나타냈다. 5) 10년(年) 이후는 매년(每年) 상호(相互) 경쟁(競爭)이 일어나기 시작하다가 13~14년경(年頃)에는 심한 경쟁(競爭)이 일어나고 있는데, 이는 상관계수(相關係數)가 급격히 낮은 수치(數値)로 떨어짐으로써 알 수 있다. 6) 간벌림(間伐林)의 간벌후(間伐後)의 생장(生長)은 인접임목간(隣接林木間)에 제약(制約)없이 정상적(正常的)인 생장(生長)을 나타냈다.

• 한국산림과학회지
• /
• 제71권1호
• /
• pp.27-32
• /
• 1985

한 임분(林分)에 있어서 개체목(個體木)의 생장(生長)은 그 임목(林木) 주변(周邊)의 주변목(周邊木)들에 의하여 커다란 영향(影響)을 받는다. 무간벌(無間伐) 임분(林分)의 경우 이러한 경향(傾向)은 임목(林木) 상호간(相互間)의 경쟁(競爭)을 통하여 더욱 현저(顯著)하게 나타난다. 본(本) 연구(硏究)는 1962년(年) Spurr가 제안(提案)한 각도합산법(角度合算法)(angle-summation method)을 이용(利用)하여 낙엽송림(落葉松林)의 개체목(個體木) 생장(生長)과 주변목(周邊木)들과의 기본적(基本的)인 생장관계(生長關係)를 조사(調査)하였으며, 이것을 기초(基礎)로 중심목(中心木)으로 선정(選定)된 각(各) 임목(林木)들의 최근(最近) 5년간(年間)의 직경생장량(直徑生長量)을 추정(推定)하기 위해 중회귀식(重回歸式)을 적용(適用)하고 그 결과(結果)를 분석(分析) 검토(檢討)하였다.

• 한국측량학회지
• /
• 제30권3호
• /
• pp.269-277
• /
• 2012

도시지역에서 가로수는 이산화탄소를 저감하고 녹지 공간을 제공하는 유용한 도시시설물 중의 하나이다. 가로수는 일반적으로 지자체에서 관리되고 있으며 가로수의 위치, 수고, 수관폭 등의 정보를 체계적으로 획득하기 위하여 항공 라이다를 사용하는 것이 효율적이다. 본 연구에서는 항공 라이다 자료에서 추정한 가로수 꼭대기점을 정제하고, 가로수의 영역을 분리하는 방법을 제안하였다. 제안 방법의 검증을 위하여 가로수의 개수, 수고, 수관폭 등을 수치적으로 정확하게 알 수 있는 모의 항공 라이다 자료를 생성하였다. 자료처리 과정은 먼저 개별 가로수의 영역을 구분하기 위하여 지면과 비지면을 구분하는 필터링을 수행하였다. 그리고 나서 비지면점에서 건물 등의 비가로수 정보를 제거하고, 가로수의 꼭대기점을 추정하였다. 가로수의 영역은 추정된 가로수의 꼭대기점과 지면점을 서로 잇는 직선의 교차점을 이용하여 설정하였다. 모의자료를 이용한 실험을 통해 수목의 꼭대기점 추정에서 발생되는 오추정점을 정제하고, 가로수의 영역설정을 통해 수고, 수관폭, 가로수의 위치정보를 획득할 수 있었다.

• 한국산림과학회지
• /
• 제96권2호
• /
• pp.160-169
• /
• 2007

The data used to develop distance-independent individual models for natural mixed forests were collected from 712 remeasured permanent sample plots (25,526 trees) of 10-year periodic from 1990 to 2000 in Baihe Forest Bureau of Changbai Mountains, northeast China. Based on analyzing relationship between diameter increment of individual trees with tree size, competitive status, and site condition, the diameter growth models for individual trees of 15 species growing in mixed-species uneven-aged forest stands, that have simple form, good predicting precision, and easily applicable, were developed using stepwise regression method. The main variables influencing on diameter increment of individual trees were tree size and competition, however, the site conditions were not significantly related with diameter increment. The tree size variables (lnDBH and $DBH^2$) were the most significant and important predictors of diameter growth existing in all 15 growth models. The diameter increment was directly proportional to tree diameter for each species. For the competitive factors in growth model, the relative diameter (RD), canopy closure (P), and the ratio of diameter of subject tree with maximum diameter (DDM) were contributed to the diameter increment at a certain extent. Other measures of stand density, such as basal area of stand (G) and stand density index (SDI), were not significantly influenced on diameter increment. Site factors, such as site index, slope and aspect were not important to diameter increment and excluded in the final models. The total variance explained by the final models of squared diameter increment ($R^2$) for all 15 species ranged from 35% to 72% and these results compared quit closely with those of Wykoff (1990) for mixed conifer stands. Using independent data set, validation measures were evaluated for predicting models of diameter increment developed in this study. The result indicated that the estimated precision was all greater than 94% and the models were suitable to describe diameter increment.

• 한국환경복원기술학회지
• /
• 제22권5호
• /
• pp.1-12
• /
• 2019

It is important to measure the height of trees as an essential element for assessing the forest health in urban areas. Therefore, an automated method that can measure the height of individual tree as a three-dimensional forest information is needed in an extensive and dense forest. Since airborne LiDAR dataset is easy to analyze the tree height(z-coordinate) of forests, studies on individual tree height measurement could be performed as an assessment forest health. Especially in urban forests, that adversely affected by habitat fragmentation and isolation. So this study was analyzed to measure the height of individual trees for assessing the urban forests health, Furthermore to identify environmental factors that affect forest growth. The survey was conducted in the Mt. Bongseo located in Seobuk-gu. Cheonan-si(Middle Chungcheong Province). We segment the individual trees on coniferous by automatic method using the airborne LiDAR dataset of the two periods (year of 2016 and 2017) and to find out individual tree growth. Segmentation of individual trees was performed by using the watershed algorithm and the local maximum, and the tree growth was determined by the difference of the tree height according to the two periods. After we clarify the relationship between the environmental factors affecting the tree growth. The tree growth of Mt. Bongseo was about 20cm for a year, and it was analyzed to be lower than 23.9cm/year of the growth of the dominant species, Pinus rigida. This may have an adverse effect on the growth of isolated urban forests. It also determined different trees growth according to age, diameter and density class in the stock map, effective soil depth and drainage grade in the soil map. There was a statistically significant positive correlation between the distance to the road and the solar radiation as an environmental factor affecting the tree growth. Since there is less correlation, it is necessary to determine other influencing factors affecting tree growth in urban forests besides anthropogenic influences. This study is the first data for the analysis of segmentation and the growth of the individual tree, and it can be used as a scientific data of the urban forest health assessment and management.

• Journal of Ecology and Environment
• /
• 제37권2호
• /
• pp.105-111
• /
• 2014

To elucidate whether small diameter at breast height correlates with tree death in an overcrowded tree population, we analyzed self-thinning occurring over the course of 37 years in naturally established Pinus densiflora populations in Sugadaira, central Japan. As trees grew, their diameters at breast height increased and the number of trees consequently decreased. Spatial distribution, which was initially clumped, changed accordingly, first becoming random and finally uniform. We calculated the "available area" of individual trees to elucidate the contribution of this parameter to tree mortality. Small diameter at breast height was strongly correlated with tree death, with a slight correlation observed between tree death and small available area of individual trees.

• 대한원격탐사학회지
• /
• 제39권5_4호
• /
• pp.1145-1153
• /
• 2023

도시 수목은 대기 중 이산화 탄소 흡수, 대기질 개선, 도시열섬 현상 완화 및 생태계서비스 제공과 같은 중요한 역할을 한다. 도시 수목을 효과적으로 관리하고 보전하기 위해서는 위치, 상태, 수종, 개체 수 등에 대한 정확한 공간 정보가 필요하다. 본 연구에서는 딥러닝 기반의 고해상도 도시 수목 면적 지도를 이용해 도시 지표면으로부터 수목을 분리하고, 국지적 최대값 필터링을 통해 수목의 위치를 정확하게 탐지하는 알고리즘을 제안한다. 도시의 다양한 생육 환경을 고려해 일률적인 필터 크기를 사용하는 대신, 수고에 따라 적절한 필터 크기를 선택해 수목 탐지 성능을 향상시켰다. 수원시 전역을 대상으로 구축한 도시 수목 위치 및 수고 정보는 도시 생태계의 지속가능한 관리와 탄소 저감 대책을 위한 기반이 될 것이다.