Context: Tree squirrels disappear when forests are clearcut. The American red squirrel (Tamiasciurus hudsonicus) and northern flying squirrel (Glaucomys sabrinus) may occupy retention forest patches on new clearcuts, but with conflicting results with respect to area, isolation, and edge effects of patches.

Aims: We tested the hypothesis that abundance, reproduction and body mass of T. hudsonicus and G. sabrinus populations would be greater in large than small patches of retention forest on new clearcuts.

Methods: We measured demographic responses of both sciurids from 2014 to 2016 in replicated (n = 4) treatments of four sizes (ha) of retention patches (means of 0.53, 1.50, 4.13 and 18.73) in south-central British Columbia, Canada.

Key results: Mean abundance of T. hudsonicus per sample line was similar among treatment sites, ranging from 0.7 to 1.7 (2014), 1.0 to 1.7 (2015) and 0.5 to 1.3 (2016). There was a positive linear relationship of mean abundance of red squirrels and increased basal area of conifers in the larger patches. Mean numbers of G. sabrinus were consistently highest in the 4.13 ha patch class in all years and appeared to decline over time in the other patches with fewest captures in the smallest patch size. There was a significant positive linear relationship between mean overall abundance of G. sabrinus and total density of overstorey trees.

Conclusions: Mean abundance, reproduction and body mass (red squirrels) of both sciurids were generally similar among patch sizes, and hence these results did not support the hypothesis.

Implications: Although our results were short-term, habitat quality was apparently sufficient to maintain the occurrence of T. hudsonicus across patch sizes ranging from 0.3 to 20.0 ha. Glaucomys sabrinus also occurred in several patches (13 of 16), albeit at low and variable numbers.

背景：砍伐森林后，松鼠消失了。美国红松鼠（Tamigasciurus hudsonicus）和北方飞松鼠（Glaucomys sabrinus）可能在新的清除地带上保留了森林斑块，但在斑块的面积，隔离和边缘效应方面却产生了矛盾。

目的：我们检验了以下假设：在新的清除地带上，沙丁鱼和沙丁鱼种群的丰度，繁殖和体重在较大范围内要大于小片保留林。

方法：我们 在加拿大不列颠哥伦比亚省中南部的四种大小（ha）保留斑块（平均值为0.53、1.50、4.13和18.73）的重复（n = 4）处理中，测量了2014年至2016年两种钉虫的人口统计学响应。

关键结果：治疗地点之间每个样本线的T. hudsonicus平均丰度相似，范围从0.7到1.7（2014年），1.0到1.7（2015年）和0.5到1.3（2016年）。在较大的斑块中，红松鼠的平均丰度与针叶树的基础面积增加呈正线性关系。在4.13公顷的斑块类别中，金缕梅的平均数一直以来都是最高的，而在其他斑块中，最小的斑块捕获最少，其平均数似乎随着时间的推移而下降。G. sabrinus的平均总丰度与高大乔木的总密度之间存在显着的正线性关系。

结论：斑块大小中两个小孢子虫的平均丰度，繁殖力和体重（红松鼠）通常相似，因此这些结果不支持该假设。

启示：尽管我们的研究结果是短期的，但栖息地的质量显然足以维持从0.3到20.0公顷的斑块大小上的T. hudsonicus的发生。青光眼sabrinus也出现在几个斑块中（16个中的13个），尽管数量很少且变化很大。