Spatial distribution of root systems of Pinus sylvestris var. mongolica trees with different ages in a semi-arid sandy region of Northeast China
Spatial distribution of root systems of Pinus sylvestris var. mongolica trees with different ages in a semi-arid sandy region of Northeast China
复制标题
樟子松根系的空间分布。
DOI：
10.1016/j.foreco.2020.118776
复制
发表时间：
2020-11
影响因子：
3.7
通讯作者：
Zhang Jinxin
中科院分区：
文献类型：
--
作者：
Zhang Ting;Song Lining;Zhu Jiaojun;Wang Guochen;Li Mingcai;Zheng Xiao;Zhang Jinxin
樟子松（Pinussylvestrisvar.mongolica）是半干旱桑迪最重要的固沙树种，在人工林中种植约35-40年后发生枯死。水分限制被认为是一个重要的原因枯死。根系的空间分布在决定树木对水资源的利用方面起着关键作用。然而，不同树龄樟子松的空间分布规律至今仍不清楚，这限制了我们对樟子松枯梢病发生机理的认识和樟子松人工林的管理。利用探地雷达对10、20、30、40、50年生樟子松粗根（根径≥ 5 mm）的水平和垂直分布进行了研究。同时采用土芯法测定了细根（RD ≤ 2 mm）的分布。结果表明，粗根与林木的水平距离随树龄的增加而增加，3.0-4.0米为10-和20岁的树木，约。6.1 30年和40年生树木的平均生长速率为4.85 m，而50年生树木的平均生长速率仅为4.85 m。10年生和20年生（约100 ~ 200年生）树木细根密度在距树木4.0 m范围内保持相对均匀。0.02 30、40和50年生的树木，随着距树距离的增加，其含量急剧下降（0.015-0.025 mg cm− 3，距树1.0 m处至约1.0 m处）。0.00 mg cm− 3（距树木5.0或6.0 m处）。在垂直方向上，10、20、30、40和50年生的粗根95%的生根深度分别为83.5、99.9、123.6、105.2和125.9cm，而10、20、30、40和50年生的粗根95%的生根深度分别为140.6、152.2、135.5、135.5和135.5cm，细根分别为144.2和127.0cm。这些结果表明，樟子松根系的空间分布萎缩的50年生树木，可能是由于接近成熟阶段的种植园网站。根据根系的空间分布，建议根据树木根系所占面积确定林分密度，以避免因水分竞争而导致的顶枯或死亡，即，10年、20年、30年和40年树龄的树木分别为403-515、321-402、217-290、139-179株ha-1（50年树龄的种植园无，因为它们已接近成熟阶段）。我们的研究结果为半干旱和干旱桑迪地区人工林的密度优化提供了新的见解。
Mongolian pine (Pinus sylvestrisvar.mongolica), the most important tree species for sand fixation in semi-arid sandy lands, experiences dieback in plantations after approximately 35–40 years since planting. Water limitation was considered as an important cause for the dieback. The spatial distribution of root systems plays a key role in determining water resources used by trees. However, it is still unknown for the spatial distribution of Mongolian pine trees with different ages, which constrains our understanding of the mechanism underlying the dieback and management of Mongolian pine plantations. Horizontal and vertical distributions of coarse roots [root diameter (RD) ≥ 5 mm] of Mongolian pine trees with 10, 20, 30, 40, 50 years old were estimated by ground-penetrating radar. Meanwhile, the distributions of fine roots (RD ≤ 2 mm) were simultaneously measured using soil coring method. Results showed that the horizontal distance of coarse roots from trees increased with tree ages up to 30–40 years, i.e., 3.0–4.0 m for 10- and 20-year-old trees, ca. 6.1 m for 30- and 40-year-old trees; but merely 4.85 m for 50-year-old trees. The fine root densities kept relatively even within 4.0 m from the trees for 10- and 20- year-old trees (ca. 0.02 mg cm−3), whereas, they decreased sharply with increasing of distances from the trees for 30-, 40- and 50-year-old trees (0.015–0.025 mg cm−3at 1.0 m from trees to ca. 0.00 mg cm−3at 5.0 or 6.0 m from trees). In the vertical direction, the rooting depth, at which 95% of roots located, was 83.5, 99.9, 123.6, 105.2 and 125.9 cm for the coarse roots of 10-, 20-, 30-, 40- and 50-year-old trees, respectively, whereas it was 140.6, 152.2, 135.5, 144.2 and 127.0 cm for fine roots, respectively. These findings indicated that the spatial distribution of roots of Mongolian pine trees shrank for the 50-year old trees, possibly due to being close to mature stage in plantation sites. Based on spatial distribution of roots, we suggested that the stand densities should be determined according to the area occupied by tree root systems in order to avoid the dieback or mortality due to water competition, i.e., 403–515, 321–402, 217–290, 139–179 trees ha−1for 10-, 20-, 30- and 40-year-old trees, respectively (none for 50-year-old plantations as they were close to mature stage). Our findings provide new insights into stand density optimization of plantations from tree belowground competition for water in semi-arid and arid sandy regions.
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影响因子：
3.7
作者：
S. Puri;Virendra Singh;B. Bhushan;S. Singh
通讯作者：
S. Puri;Virendra Singh;B. Bhushan;S. Singh
影响因子：
4.9
作者：
Kira A. Borden;S. Thomas;M. Isaac
通讯作者：
Kira A. Borden;S. Thomas;M. Isaac
影响因子：
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作者：
Si Jian-hua
通讯作者：
Si Jian-hua
影响因子：
2.2
作者：
Jennifer N. Bennett;B. Andrew;C. Prescott
通讯作者：
Jennifer N. Bennett;B. Andrew;C. Prescott
影响因子：
6.2
作者：
Xiaolin Song;Xiaodong Gao;M. Dyck;Wei Zhang;Pute Wu;Jie Yao;Xining Zhao
通讯作者：
Xiaolin Song;Xiaodong Gao;M. Dyck;Wei Zhang;Pute Wu;Jie Yao;Xining Zhao