Ảnh hưởng của cạnh tranh cùng loài đến sinh trưởng của cây ở rừng trồng thông Hàn Quốc

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Tác giả: Thanh Tuấn Nguyễn, Hai Long Shen, Đình Duy Vũ

Ngôn ngữ: Vie

Ký hiệu phân loại:

Thông tin xuất bản: Sinh học 2020

Mô tả vật lý:

Bộ sưu tập: Metadata

ID: 396329

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Bài báo sử dụng số liệu thu thập từ 15 ô tiêu chuẩn định vị rừng trồng thuần loài thông Hàn Quốc (Pinus koraiensis) tại lâm trường Mộng Gia Cương, Đông Bắc Trung Quốc, thông qua một số phương pháp phân tích tương quan và mô hình hồi quy để làm rõ mối quan hệ giữa chỉ số cạnh tranh với sinh trưởng, tăng trưởng của cây riêng lẻ. Kết quả nghiên cứu cho thấy, chỉ số cạnh tranh phụ thuộc vào khoảng cách có tương quan nghịch với tăng trưởng 5 năm đường kính cây (P <
0,05) và có tương quan cao hơn so với chỉ tiêu không phụ thuộc vào khoảng cách. Trong các chỉ số cạnh tranh phụ thuộc vào khoảng cách, chỉ số cạnh tranh CI1-M2 có tương quan lớn nhất với tăng trưởng cây rừng, mặt khác hệ số tương quan ổn định ở tất cả các mật độ nghiên cứu. Do đó, bài báo đã sử dụng chỉ số CI1-M2 để nghiên cứu sinh trưởng và xây dựng mô hình dự đoán tăng trưởng của P. koraiensis. Chỉ số cạnh tranh CI1-M2 có mối quan hệ tuyến tính dương với đường kính ngang ngực, đường kính tán, thể tích và tiết diện ngang của cây (P <
0,05). Ngược lại, Chỉ số cạnh tranh có quan hệ tuyến tính âm với chiều cao dưới cành (P <
0,05) và không có quan hệ với chiều cao. Với các biến đầu vào là các chỉ tiêu điều tra cây cá thể và chỉ số cạnh tranh CI1-M2, thông qua các bước phân tích hồi quy mô hình tăng trưởng 5 năm của đường kính cuối cùng chỉ còn lại 2 biến số là đường kính ngang ngực (LnD) và chỉ số cạnh tranh CI1-M2. Hơn nữa, sau khi đưa biến chỉ số cạnh tranh vào biến dự đoán thì độ chính xác của mô hình tăng lên rõ rệt với sai số tuyệt đối trung bình giảm từ 22−25%., Tóm tắt tiếng anh, The aim of this study was to explore the correlation of competition indices (CIs) on individual tree growth for Korean pine (Pinus koraiensis) plantation using partial correlation analysis and generalized linear models. The data were collected from 15 permanent plots in Mengjiagang forestry farm, Northeast China. The results showed that the distance dependent CIs have a higher predictive capacity for individual growth of pine trees. The control index of competitive trees number (CI1) combined with the selection fixed competitor trees (M2) was found to be the most well correlated competition measure with five-years diameter increment. Thus, the competition index (CI1- M2) was recommended for developing individual tree growth models. The subject tree diameter at breast height, crown width, height to crown base, tree volume and basal area all showed a significantly linear correlation with tree competition intensity (P <
0,05). Diameter at breast height, crown width, tree volume and basal area all decreased with increasing competition intensity, whereas the height to crown base increased. There was no significant relationship between competition intensity and tree height (P >
0,05). The optimal model of predicting individual growth with logarithm of diameter at breast height and CIs as the independent variables due to the best fitting performance. This results also showed considerable improvement in predicting individual tree periodic growth when including competition indices that the mean absolute error is reduced in the range of 22−25%.

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