Tree regeneration after fire: Delta 1994 burn surveys, pre-fire stem counts and basal areas, for species other than black spruce

Data for this study were collected in 2001 and 2002 by Jill Johnstone (University of Alaska Fairbanks) and Eric Kasischke (University of Maryland). Sites were located within the perimeter of the 1994 burn southeast of Delta Junction Alaska, USA, bordering the Alaska Highway to the North and the Gerstle River to the West. Sites were selected from satellite classifications prepared by Eric Kasischke to represent different levels of burn severity and post-fire vegetation canopy greenness (NDVI). Site selection was constrained by road access, and only areas where all trees had been killed by the fire were selected.

At each site, a central point was located in an area of visually homogeneous vegetation. Five parallel transects, each 50 m long, were laid out as follows:

1) the first transect started at the central point and followed a randomly-selected compass direction,

2) two additional transects were established parallel to the first, but at a random distance from the central transect up to 25 m distant.

Vegetation was sampled in a 2-m wide belt centered on each transect, and soil samples were made at intervals along the transect line. Vegetation measurements included:

a) basal diameters of all pre-fire trees greater than 1.3 m in height,

b) counts of all post-fire tree seedlings, and

c) basal diameters of tree seedlings and willows, measured in a randomly chosen 5x2 m portion of each transect.

General notes were made on visual percent cover of different vegetation growth forms at the site. Destructive measurements of tree seedlings and willows made in 2001 were used to develop allometric equations to predict dry biomass from basal diameter. Measurements of soil organic layer depth were made at 5 m intervals with the use of a spade to excavate small chunks of sod. At one randomly-selected sample point per transect, a 10x10 cm sample of the organic layer was collected for bulk density measurements. Bulk density samples were dried in a 60degC oven for 48 hours and then weighed. Information on the soil profile to 50-100 cm depth was collected from a single soil pit at the site.

The purpose of the study was to document variations in post-fire tree establishment and woody biomass accumulation that could be related to variations in fire severity or pre-fire vegetation characteristics. Data from the study have not yet been published as of 2003.

Data in rows.

Contains pre-fire stem counts and basal areas, for species other than black spruce.

本研究的数据由阿拉斯加费尔班克斯大学的吉尔·约翰斯通（Jill Johnstone）与马里兰大学的埃里克·卡西斯克（Eric Kasischke）于2001年和2002年采集。样地位于美国阿拉斯加州德尔塔章克申东南部1994年过火区范围内，北邻阿拉斯加公路，西接格斯特尔河。样地由埃里克·卡西斯克基于卫星分类结果选取，以代表不同火烧烈度与火后植被冠层归一化差异植被指数（NDVI）绿度水平。样地选取受道路可达性限制，仅纳入所有树木均被火烧死的区域。

在每个样地中，中心点设置在植被外观均一的区域。共布设5条平行样线，每条长50米，布设方式如下：1）第一条样线从中心点出发，沿随机选定的罗盘方向延伸；2）另外两条样线与第一条平行，与中心样线的随机距离不超过25米。

以每条样线为中心设置2米宽的植被样带进行植被采样，并沿样线间隔采集土壤样品。植被测量指标包括：a）所有火前高度大于1.3米的树木的基径；b）所有火后树苗的数量；c）在每条样线随机选取的5×2米区域内，测量树苗与柳树的基径。同时记录样地内不同植被生长型的目视百分盖度。

2001年开展的树苗与柳树破坏性采样，被用于构建异速生长方程，以通过基径预估植株干生物量。采用铁锹挖掘草皮块的方式，每5米测量一次土壤有机层深度。在每条样线的随机采样点处，采集10×10厘米的有机层样品用于容重测定：样品先在60℃烘箱中烘干48小时，随后称重。在每个样地的单个土壤坑中，采集深度为50至100厘米的土壤剖面信息。

本研究旨在记录火后树木定植与木本生物量积累的变化，此类变化可能与火烧烈度或火前植被特征相关。截至2003年，该研究的数据尚未发表。

数据以行式存储。数据集包含除黑云杉外其他树种的火前茎秆数与基面积。