The caloric values of vegetation are indicative of energy conversion in the forest ecosystem, and serve as a measure of the energy that plants contain. Studies of seasonal changes in the caloric values of vegetation play a valuable role in promoting forest productivity and systemic energy input. Energy analyses are a method of evaluating the structure and function of a forest ecosystem, and contribute to the promotion of forest stand productivity by representing the amount of solar energy available to the vegetative community. Research on plant energy resource development has been conducted in the interest of alleviating the energy crisis and facilitating the conservation of the ecological environment. In this study, we conducted contrastive analyses of the caloric values and standing crop energy from different 5 diameter classes of organs of the 24-year-old Larix olgensis Gmelinii plantation on Mopan Mountain, in order to study their capacity to accumulate and store energy. The resulting knowledge of Larix olgensis Gmelinii plantation productivity will provide theoretical guidance for the improvement of Larix olgensis Gmelinii plantation management.
Three healthy plants were sampled in plots on a Larix olgensis Gmelinii plantation, tree organs in 5 different diameter classes were collected, with 4 cm as one differentiating level. A Monsic layering and cutting method was adopted on the ground, to measure the characteristics of fresh trunk, bark, branch, and leaf material with 2 m as one differentiating level. A standard underground root evaluation method was adopted to measure the characteristics of roots. To ensure the accuracy of the data and effective, the following material was collected:trunk at breast height, 1- to 2-year-old branch bark, perennial branch bark, trunk bark, 1- to 2-year-old branches, and perennial branches. As for leaf material, the canopy was divided into 3 layers, and leaves were collected from the east, south, west, and north of each layer. To collect root material, the root system was subdivided into root stumpage, thick roots, mid-roots, and thin roots. Caloric values were measured to study the 5 diameter classes of various Larix olgensis Gmelinii organs. The total standing crop energy of Larix olgensis Gmelinii was studied in addition to the biomass data.
The results showed that in order to quantify the total standing crop energy in each Larix olgensis Gmelinii organ, W=aD^b was the most suitable model for projecting the total standing crop energy of in Larix olgensis Gmelinii trees. The calorific values of various Larix olgensis Gmelinii organs were ordered as follows:branch > bark > trunk > leaf > root. The total standing crop energy of different Larix olgensis Gmelinii organs was ordered as follows:trunk > root > bark > branch > leaf. The total standing crop energy was 1988.39×10⁹ J/hm², with that of the aboveground material (mainly concentrated among 0-12 m plants) being far greater than that of the underground material (mainly concentrated in root stumpage and thick roots). Contrastive analyses of the total standing crop energy in 5 diameter-classes of roots suggested that 20 cm diameter-class roots contain the highest total standing crop energy, at 187.73×10⁹ J/hm², and 8 cm diameter-class root contain the lowest total standing crop energy, at 7.72×10⁹ J/hm². Contrastive analyses of the total standing crop energy in 5 diameter-classes of Larix olgensis Gmelinii organs suggested that the 16 cm diameter-class contained the highest total standing crop energy, at 723.45×10⁹ J/hm², and the 8 cm diameter-class contained the lowest total standing crop energy, at 46.58×10⁹ J/hm². Comparison of the total standing crop energy between Larix olgensis Gmelinii and mongolica Litv, revealed that the total standing crop energy of Larix olgensis Gmelinii was lower than that of mongolica Litv.