Data to estimate stand density and average basal diameter from unburned black spruce stands used in the effects of variations in post-fire organic layer thickness studies in the Delta Junction region, 1995-2003

This database contains data on basal diameter and distances from a center point to the trees sampled, which is used to estimate stand density in unburned black spruce plots used in an analysis of variations in the depths of surface organic layers found in burned and unburned black spruce stands, and the effects of variations in depth of burning on soil temperature and moisture, and organic layer carbon stocks. Data for the overall study were collected between 1995 and 2003 by Eric Kasischke (University of Maryland), Kathy O?Neill (Duke University), and Jill Johnstone (University of Alaska Fairbanks). Sites were located in burned black spruce stands within the perimeters of three recent fires (1987, 1994, and 1999), unburned black spruce stands adjacent to the burned stands, and within one black spruce stand that burned in 1956. The three fires were: (a) the 1987 Granite Creek fire located 15 km to the east of Delta Junction, Alaska USA, bordering the Alaska Highway on the North and Jarvis Creek on the south; the 1994 Hajdukovich Creek fire located 45 km southeast of Delta Junction Alaska, USA, bordering the Alaska Highway to the North and the Gerstle River to the West, and the 1999 Donnelly Flats fire, located 8 km south of Delta Junction, bordering Jarvis Creek to the east and the Richardson Highway on the west. Data that were collected and are in databases associated with this project include: (1) organic layer depths in burned stands; (2) organic layer depths in unburned stands; (3) basal diameters of overstory trees in unburned stands and distance measures that can be used to estimate stand density; (4) mineral soil temperature and moisture data in burned stands; (5) mineral soil temperature and moisture data in unburned stands; and (6) bulk density and percent carbon data from different organic layers in unburned stands.

本数据库收录了未火烧黑云杉林分样地内采样树木的基径（basal diameter）以及采样树距中心点的距离数据，该数据集用于估算林分密度（stand density），相关研究旨在分析火烧与未火烧黑云杉林分的地表有机质层（surface organic layers）深度变异特征，以及火烧深度变异对土壤温度、湿度及有机质层碳库（organic layer carbon stocks）的影响。
本研究的整体数据采集工作于1995年至2003年间完成，由埃里克·卡希施克（Eric Kasischke，马里兰大学）、凯西·奥尼尔（Kathy O’Neill，杜克大学）以及吉尔·约翰斯通（Jill Johnstone，阿拉斯加大学费尔班克斯分校）负责实施。
研究样地分为三类：一是三处近期火烧迹地内的火烧黑云杉林（分别对应1987年、1994年及1999年火灾迹地），二是紧邻火烧迹地的未火烧黑云杉林，三是1956年发生过火烧的一处黑云杉林。三处火灾的具体位置信息如下：（a）1987年花岗岩溪（Granite Creek）火灾：位于美国阿拉斯加州德尔塔章克申以东15公里处，北临阿拉斯加公路，南接贾维斯溪；1994年哈杜科维奇溪（Hajdukovich Creek）火灾：位于美国阿拉斯加州德尔塔章克申东南45公里处，北临阿拉斯加公路，西接格斯特尔河；1999年唐纳利平地（Donnelly Flats）火灾：位于德尔塔章克申以南8公里处，东接贾维斯溪，西临理查森公路。
本项目关联数据库中收录的采集数据包括：（1）火烧林分的地表有机质层深度数据；（2）未火烧林分的地表有机质层深度数据；（3）未火烧林分上层林木的基径数据，以及可用于估算林分密度的距离测量数据；（4）火烧林分的矿质土壤温度与湿度数据；（5）未火烧林分的矿质土壤温度与湿度数据；（6）未火烧林分不同有机质层的容重及碳百分含量数据。