Lab 4 Data - Tree Growth

Authors: Kamil Adamczewski, Joelle Brooker, Brittney Jorisch, and Karin Yosefi On Thursday, October 15th, 2015, at 3:00 pm and on Thursday, October 22nd, 2015, at 3:10 pm, 50 different individuals of Maple trees in the Danby Woodlots at the north-east side of York University were randomly selected and observed for 3 different variables. The first was the diameter at breast height (dbh) of the Maple tree as an indication of tree growth. This was determined by using a transect and measuring the diameter of the trunk of the Maple tree starting at the zero mark and at a constant breast height of approximately 1.6 metres. This was recorded in centimeters. The second was the percentage of canopy coverage surrounding the randomly selected Maple tree being observed as an indication if the amount of light the Maple tree is receiving. This was approximated by creating a square with the thumb and forefinger of each hand and raising the square up towards the canopy directly surrounding the Maple tree. It was then determined how much of the total square was being covered by the canopy. It was measured as a percentage out of 100. 0 being no coverage at all and 100 being complete coverage of the square. Canopy of all tree species in the vicinity was included in this measurement. The third variable was abundance of other plant organisms surrounding the Maple tree found within a 3 by 3 metre quadrat as an indication of the density of life around the Maple tree. This was approximated by using 2 transects measured at 3 metres and placing them to create one corner of the quadrat, the other corner was estimated by using the end points of the laid out transects. The Maple tree being oberved was roughly in the centre of the quadrat. Observation was done by walking within the quadrat and noting the quantity of any other plant organisms within the quadrat. This quantity did not include any dead organisms, but did include grasses and small shoots found. The purpose of these observations was to determine if there is a relationship between tree growth, light and density. The data was collected in the Danby Woodlot, at the north-east side of York University, Keele campus. The Danby Woodlot is a fairly dense area of various species of trees including Maple and Oak trees. There is a slight amount of dead or broken trees and branches littering the ground. On the first date, October 15th 2015, the temperature was 11 degrees Celcius, and it was very windy and cloudy with mild percipitation. On the second date, October22nd 2015, the temperature was 13 degrees Celcius, and it was sunny with a few clouds and slightly windy. The sample size was 50 Maple trees.

作者：卡米尔·亚当切夫斯基（Kamil Adamczewski）、乔尔·布鲁克（Joelle Brooker）、布里特尼·约里施（Brittney Jorisch）与卡琳·约塞菲（Karin Yosefi）。2015年10月15日周四下午3时，以及2015年10月22日周四下午3时10分，研究人员于约克大学（York University）东北侧的丹比林地（Danby Woodlots）随机选取50株不同的枫树开展观测，记录3项变量。
第一项变量为枫树的胸径（diameter at breast height, dbh），用以表征树木生长状况。测量采用样带法，以约1.6米的标准胸高处为测量点位，从刻度零点开始测量枫树树干直径，单位为厘米。
第二项变量为目标枫树周边的冠层覆盖率百分比，用以表征枫树接收的光照水平。测量方式为：双手拇指与食指围成正方形，将该正方形置于目标枫树周边冠层的正上方，估算正方形总面积内被冠层覆盖的比例，以百分比计，0代表完全无冠层覆盖，100代表正方形完全被冠层覆盖。本次测量涵盖周边所有树种的冠层。
第三项变量为3米×3米样方（quadrat）内枫树周边其他植物的丰度，用以表征枫树周围的生物密度。测量方式为：铺设两条长度为3米的样带，以其交点作为样方的一个顶点，利用样带端点确定样方其余两个顶点，目标枫树大致位于样方中心。观测者进入样方内统计其中所有非死亡的植物有机体数量，统计范围包含草本植物与幼芽，但不包括死亡有机体。
本次观测的目的为探究树木生长、光照条件与生物密度三者间的关联。数据采集于约克大学基尔校区（Keele campus）东北侧的丹比林地。丹比林地植被茂密，涵盖枫树、橡树等多个树种，地面散落少量枯树与断枝。
2015年10月15日首次观测时，气温为11摄氏度，天气多风多云，伴有小幅降水；2015年10月22日第二次观测时，气温为13摄氏度，晴到多云，风力偏弱。本次观测样本量为50株枫树。