Forest Growth and Yield

Safflower may have a certain production potential under German conditions, particularly in organic farming where the putatively low nutrient requirement is highly welcomed. However, current knowledge regarding the nutrient requirements of safflower as compared to similar oil crops is limited. It was thus the aim of this study to determine the growth and yield response of safflower (Carthamus tinctorius L.) as compared to sunflower (Helianthus annuus L.) with respect to potassium (K) supply. Three safflower and two sunflower plants were cultivated in 5 L Mitscherlich pots. Both species responded strongly to increasing K supply with respect to plant growth and yield. Growth and yield of safflower increased up to 1 g K per pot, while the optimum for sunflower was 3.0 g K per pot. Safflower out-yielded sunflower at low K supply, while at high K level, the opposite was observed. Supply of K affected virtually all yield components in both species, though to different degree. The number of capitula in safflower was only slightly affected, and the number of achenes per capitulum was only reduced under severe K deficiency, while single-achene mass increased with increasing K supply. In sunflower, the number of achenes per capitulum strongly responded to the K supply, as did the single-achene mass. Oil yield in safflower was affected by K deficiency mainly due to reduced achene yield, not oil concentration. However, oil yield in sunflower was severely affected by low K supply due to both reduced achene yield and lowered oil concentration. Multiple-regression analyses indicate that in sunflower, the stem dry matter (DM) and the total amount of K accumulated in the aboveground biomass were most important, while in safflower the total amount of K and N accumulated had the highest impact. It is concluded that sunflower is more sensitive to inadequate K supply than safflower.

Mulching is one of the important agronomic practices in conserving the soil moisture and modifying the soil physical environment. Wheat, the second most important cereal crop in India, is sensitive to soil moisture stress. Field experiments were conducted during winter seasons of 2004–2005 and 2005–2006 in a sandy loam soil to evaluate the soil and plant water status in wheat under synthetic (transparent and black polyethylene) and organic (rice husk) mulches with limited irrigation and compared with adequate irrigation with no mulch (conventional practices by the farmers). Though all the mulch treatments improved the soil moisture status, rice husk was found to be superior in maintaining optimum soil moisture condition for crop use. The residual soil moisture was also minimum, indicating effective utilization of moisture by the crop under RH. The plant water status, as evaluated by relative water content and leaf water potential were favourable under RH. Specific leaf weight, root length density and dry biomass were also greater in this treatment. Optimum soil and canopy thermal environment of wheat with limited fluctuations were observed under RH, even during dry periods. This produced comparable yield with less water use, enhancing the water use efficiency. Therefore, it may be concluded that under limited irrigation condition, RH mulching will be beneficial for wheat as it is able to maintain better soil and plant water status, leading to higher grain yield and enhanced water use efficiency.

Tree growth variables are important tree characteristic connected to forestry activities. This study focused on crown width as it reflects general tree health and provide habitat to diverse plants and animals. Therefore, this research work aimed to develop and validate a crown width prediction models for sustainable management of Gmelina arborea in Federal University of Technology, Akure, Nigeria. Three linear and nonlinear models were fitted for the prediction of crown-width using diameter at breast height (Dbh), total tree height and tree Slenderness coefficient as the predictive variables. Performance of the models was ranked according to best fit using the Akaike information criterion (AIC) and adjusted coefficient of determination (Radj 2). The result showed that crown width was significant and shows strong correlation with other tree growth variables. The selected models showed high value of adjusted coefficient of determination. Although, it was revealed that multiple linear-binomial and polynomial model had the highest adjusted coefficient of determination (Radj 2 = 98%) but binomial model had the least Akaike information criterion (AIC=-637.46) which make it to be rank as the best model, while monomolecular non-linear model had the least adjusted coefficient of determination (Radj 2 = 93%) and largest Akaike information criterion (AIC=-359.12).

Subiakto A, Rachmat HH, Sakai C. 2016. Choosing native tree species for establishing man-made forest: A new perspective for sustainable forest management in changing world. Biodiversitas 17: 620-625. Establishment of tree plantation on degraded lands and forest clearly favored some exotic species such as Gmelina arborea, Acacia, and Eucalyptus. High productivity, less harvesting time, and deeper silvicultural knowledge are the beneficial factor for choosing those exotics species. However, the use of a wide variety of native tree species becomes more significantly important in reforestation projects due to the greater biodiversity benefits and wider environmental services. This research was carried out as a multiyear observation and continuous experiment to value how native tree species can be prospective alternatives in providing and supporting human need. The performances of two native Indonesian Shorea species, Shorea leprosula and Shorea selanica, were evaluated at a dipterocarp planting trial in two different sites in Indonesia. Growth data was obtained from 15 and 17 years old plots, twelve 100 m X 100 m square plots on mineral soils (Gunung Dahu Experimental Forest/GDEF, Bogor) and eight resembled plots on frequently flooded peat land (PT. Arara Abadi/PT. AA, Riau). Survival rates were varied, ranged from 36-77%, diameter at breast height from 13.7-24.9 cm, tree height from 10.8-16.9 m, mean volume from 0.119 m 3 /tree-0.567 m 3 /tree, and total volume from 79.420 m 3 /ha-215.412 m 3 /ha. Growth rates of planted saplings were affected by species, site and spacing distance. The development of man-made dipterocarps forest in the tropic, especially in South East Asia can be as prospective as developing an exotic fast growing plantation. Eventhough in situ conservation would give the most benefit in conserving genetic resources of native tree species, establishing man-made dipterocarp forest still have higher environmental value than using exotic tree species such as acacia. Moreover, establishing man-made dipterocarp forest is considered more environmental friendly and possess lower to no risk of species invasion compare to those of developing exotic trees plantation. Abbreviations: GDEF = Gunung Dahu Experimental Forest, PT. AA = PT. Arara Abadi, S. leprosula = Shorea leprosula, S. selanica = Shorea selanica.