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Quantification of individual tree competition index taking Chinese-fir plantations in subtropical low hilly area as an example

100%

Zhang Y., Deng X., Huang Y., Li Y., Xiang W., Yan W.

Polish Journal of Ecology

2019

tom 67

nr 1

Competition among trees is a fundamental interaction process within plant community, which is the theoretical basis of thinning. Plant competitive intensity is generally measured using a competition index (CI) that can be classified into two major categories: distance-independent and distance-dependent. The current study used Cunninghamia lanceolata (Lamb.) Hook as the test subject and used Hegyi's CI (distance-dependent), to quantify individual CI and their relationship with tree diameter at breast height (DBH). Five different criteria were used to select potential competitors for the calculation of CI. Seven basic linear and nonlinear mathematical functions were used to test and quantify the relationships between DBH of the target tree and the individual CI. Results showed that individual CI was negatively correlated with target tree DBH: as DBH increased, competition intensity weakened. The adjusted R² with five different criteria of selection competitors simulated by seven functions ranged from 0.30 to 0.82. Considering the root mean square error (RMSE), P-value, and adjusted-R², our results suggested that the best model to simulate the relationship between individual CI and focal tree DBH was power function (CI = 43.98 × DBH⁻¹‧⁰⁸, adjusted R² = 0.81) and with the Voronoi diagram method as the criteria for selecting competitors. These results can demonstrate a clearer understanding of the spatial structure of forests, and can be used to guide the selection of thinning trees in the process of thinning practice.

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Shoot and root competition between spring triticale and field beans during early growth

80%

Sobkowicz P.

Acta Scientiarum Polonorum. Agricultura

2005

tom 04

nr 1

The experiment was carried out according to additive design to study shoot and root competition between spring triticale and field bean during early stages of plant growth. It was conducted in plastic boxes 76 cm long, 15 cm wide and 15 cm deep, filled with 16 kg of aerial dry alluvial sandy loam soil, containing 15-20% of silt. The soil was classified as good rye agricultural suitability complex. Appropriate arrangement of boxes and aboveground aluminium foil partitions allowed separating four competition treatments: no competition, shoot, root and shoot + root competition. The results of the experiment showed that at the beginning of species interaction in triticale-field bean intercrop system, root competition is more intense than shoot competition. Triticale outcompeted field bean when crops interacted with their roots, but when only shoots competed, field bean tended to be the dominant species. The study presented did not show definitely that cereal is better competitor than legume during early stages of plant growth.

Ograniczanie wyników

1 Acta Scientiarum Polonorum. Agricultura

1 Polish Journal of Ecology

1 Deng X.

1 Huang Y.

1 Li Y.

1 Sobkowicz P.

1 Xiang W.

1 Yan W.

1 Zhang Y.

1 2019

1 2005

Wyniki wyszukiwania

Quantification of individual tree competition index taking Chinese-fir plantations in subtropical low hilly area as an example

Shoot and root competition between spring triticale and field beans during early growth