Key Engineering Materials Vol. 500 (2012) pp 175-179

Online available since 2012/Jan/24 at www.scientific.net

© (2012) Trans Tech Publications, Switzerland

doi:10.4028/www.scientific.net/KEM.500.175

Three-Dimension Green Biomass and Ecological Benefit Assessment of10- to 15-year-old Taxus

Chinensis Var. Mairei

Liangsong Li 1, 2 ,Jing Xie3,4

1College of Forestry, Beijing Forestry University, Beijing, China

2Beijing University of Chinese Medicine, Beijing, China

3College of Nature Conservation,Beijing Forestry University,Beijing ,China

4Department of Environmental Sciences, University of Toledo, Toledo, OH, USA

Keywords: Taxus chinensis var. maire, Three-dimension green biomass, Ecological benefit, Assessment index, Model

Abstract：Taxus chinensis var. maire is an important medicinal, ecological and environmental friendly plant. To propose calculation methods of three-dimensional ecological benefit assessment index of Taxus chinensis var. maire, 10 main indicators of 90 Taxus chinensis var. maire at the age of 10 to 15 were measured and calculated, including heights of trees and crowns, diameter of crowns and roots, largest vertical section area of crowns, numbers of branches and leaves, length, width and area of leaves, based on consideration of situations such as altitude, coordinates, solar radiation, mean annual sunshine hours, rainfall and temperature, days with 4 or more than 4 power wind, frost-free period, etc. Ecological benefits of Taxus chinensis var. maire were analyzed using two-and three-dimensional models based on the research of three-dimensional vegetation volume, and the main results were analyzed and summarized. This will provide a scientific assessment standard for exploitation and territory plantation of Taxus chinensis var. maire.

Introduction

Taxus chinensis var. maire is not only an important medicinal plant, but also an important ecological and environmental friendly plant in China. Taxus chinensis var. maire, whose scientific name is Taxus chinensis (Pilger) Rehd. var. mairei (Lemee et Levl.) Cheng et L.K. Fu, is also called Beauty Taxus, Red Torreya and Yew, belonging to Taxaceae, genus Taxus, which has been recognized as National Grade 1 Key Protected Wild Plant [1, 2]. In recent years, the scale of Taxus chinensis var. maire artificial cultivation has grown bigger and bigger since Taxus chinensis var. maire becomes more and more attractive in tumors prevention and cure, territory plantation, courtyard appreciation, etc. Over the past 10 years, cultivation area for Taxus chinensis var. maire accumulatively reaches 1.2×109 m2 in China and it has become the largest cultivation medicinal plant [3]. Consequently, comprehensive research on ecological benefits, and analysis and induction using mathematical model were carried out based on the summaries of three-dimensional vegetation volume.

Materials and Methods

Research area was a 5 km2 region (27°35´35" N, 118°51´33" E). On the basis of current data, 95320 Taxus chinensis var. maire were compiled, including 1096 at the age of 10 to 15. We selected 90 Taxus chinensis var. mairei at the age of 10 to 15 (15 samples for each age). Soil area and volume controlled by roots besides heights of trees (TH(m)) and crowns(CH(m)), diameter of crowns (CD(m)) and roots (RD(cm)), largest vertical section area of crowns (CLVSA(m2)), numbers of branches (BN(#)) and leaves (LN(#(104))), length (LL(cm)), width (LW(cm)) and area (LA(m2m–2)) of leaves were statistical analyzed in this area. Then, analysis and research combined with altitude, thickness of red soil layer, mean annual rainfall, and days with 4 or more than 4 wind powers. According to the observation data, this research region is with subtropical monsoon climate, where mean annual temperature is 18.4℃, rainfall is 1662 mm, mean daily solar radiation is 270.2 cal/cm2, mean daily sunshine hours are 4.8 h/d, and mean annual frost-free period is 260 to 290 d, mean annual more than 4 wind power days are 48 d, thickness of red soil layer is 90 cm, altitude is 280 ± 15 m. Specific research indicators were showed in table 1.

Table 1  Main indicators of Taxus chinensis var. maire

The core of this research was interrelation between three-dimension green biomass and ecological benefits. Green biomass was proposed to quantify ecologic effects of vegetation. Three-dimension green biomass was space occupied by stems and leaves of the plant [4]. In regard of energy transfer in ecology and physiological function of stems and leaves, photosynthesis probability would be greater, effects of obstructing from wind and sand would be stronger, and ecologic effects will be better, when it had more leaves and bigger crown. This research was carried out by three aspects:

First, ecological benefits of Taxus chinensis var. maire were analyzed by using two-dimensional model. The two-dimensional model took each crown as an isosceles triangle, and analyzed it according to the numbers of the units and spatial distribution, then set up corresponding mathematical models. From wind breaking and sand fixation point of view, within a certain region area, effects of obstructing from wind and sand of Taxus chinensis var. maire was directly proportional to vertical section area of each crown. So, effects of wind breaking and sand fixation were better when vertical section area of each crown is greater.

Calculation was as follows: assessment index of two-dimensional ecological benefits of Taxus  chinensis var. maire = total numbers of Taxus chinensis var. mairei × mean vertical section area of each crown ÷ total area of research region. Thus, the model was:

C2 = (L / SZ) × hS × R.                         (1)

Where C2 is assessment index of two-dimensional ecological benefits of Taxus chinensis var. maire, L is total numbers, hS is mean vertical section area of crown, SZ is total area of research region, and R is a constant (R=100). For example, when total area was 5×106 m2, total numbers of Taxus chinensis var. maire was 95320, and mean vertical section area of each crown was 3.9 m2. According to the model, result was:

C2 = (95320 / 5000000) × 3.9 × 100 = 7.435.           （2）

Second, ecological benefits of Taxus chinensis var. maire were analyzed by using three-dimensional model. According to the above calculation methods, we found that the biggest problem for two-dimensional model was simple by calculating just on flat scale, ignoring the three-dimensional distribution of leaves and branches, as well as its ecologic effects. As a result, it could not solve the assessment problems on special and systematic scales by using two-dimensional model. Three-dimensional model which based on three-dimension green biomass was an important way and method to assess comprehensive effects of plants. It is the objective and direction of this research. In order to calculate and set up model easily, we took all crowns as right pyramid although it is cone. Crown volume multiplies 95% according to cone formula (5% is deduction of invalid volume of damaged crown, which is the constant we got after many analysis). On these bases, three-dimensional ecological benefit assessment index was estimated as:

C3 = (L / SZ) × VS × R                   （3）

Where C3 is three-dimensional ecological benefit assessment index, L is total numbers, VS is mean volume of crown, Sz is total area of research region, and R is a constant (R=100). Then, result was:

C3 = (95320 / 5000000) × 3.35 × 100 = 6.439            （4）

In view of two- and three-dimensional assessment index of Taxus chinensis var. mairei, it could be found that ecological benefit assessment index were 7.435 and 6.439, respectively. According to the above assessment standard, the higher assessment index were, the greater ecological benefits were. So, two- and three-dimensional assessment index of Taxus chinensis var. maire were divided into five grades. They were excellent, good, medium, relatively poor and poor. When index was more than 20, it was excellent; between 10 and 20, good; between 5 and 10, medium; between 1 and 5, relatively poor, and less than 1, poor.

Results and Conclusions

Taxus chinensis var. maire was an important medicinal plant and territory plantation species and had significant economic, ecological and environmental friendly benefits. Currently, comprehensive and objective analyses on it ecological benefits were indispensable since it had large plantation area and wide effect region. We set up calculation methods of three-dimensional ecological benefit assessment index, making three-dimension green biomass as the research core, based on its two-dimensional ecological benefit assessment index. According to our research results, the main results were:

First, this research proposed a method of ecological benefit assessment of Taxus chinensis var. Maire: three-dimension Green Biomass and assessment of ecological benefits. There are many influencing factors on its ecological benefits, including natural factors (altitude, climate, soil and temperature) and human factors (planting area, density, techniques and management methods) [5].

Second, ecological benefits of Taxus chinensis var. maire mainly consisted of above ground level and below ground level. The above ground level benefits mainly included medicinal, timber, ecological and environmental friendly values. For medicinal values, its leaves, bark, roots and fruits could be used as medicine. Taxol extracted from Taxus chinensis var. maire was an important medicine for against leukemia and preventing and curing the tumors [6]. . For ecological values, it was an important good species for wind break and sand fixation and territory plantation and it was favorable be planted on large area [7]. For environmental friendly values, it had strong ability of adaptability and disease-resistant, and good effects of absorbing harmful gases and cleaning air.Its below ground level benefits mainly included soil and water conservation and soil environment improvement.

Third, our analyses and research were based on all kinds of growth observations data of Taxus chinensis var. maire. So, its assessment of growth trends and ecological benefits was objective. There was a lack of a comprehensive and comparative research on which were living in wild and different geographical environment, since we just collected plantation younger than 15 year’ old and observation sites were relatively single. Meanwhile, further research on its chemical composition and function of air monitoring, and on analysis of soil characters were needed. Also, we set up models just according to observations data of growth trends and external morphology, and calculating methods were relatively brief. On this basis, we hope some more comprehensive, objective and specifically assessment system would be set up in the future.

Discussion

There are three insufficiencies in this research. First, physical and chemical research of Taxus chinensis var. maire was relatively shallow. Although the observation data were accumulated, further research on trunks, branches and soil structure using physical and chemical methods are needed. Second, research on root ecological benefits was relatively simple. Just 15 trees whose roots were analyzed, so, numbers or ages of trees were not representative. Third, research methods of ecological benefits were relatively simple. We set up ecological benefit assessment index to evaluate growth condition, trends and ecological effects, but calculation methods were not comprehensive enough and quantitative standards are needed further perfection.

In a word, Taxus chinensis var. maire is an emerging ecological plant. It has multiple ecological effects of wind break and sand fixation, reducing wind speed, water conservation and improving environment, etc. Research and analyses on its ecological benefits based on three-dimension green biomass has positive practical values and guiding significance for assessment of exploitation and territory plantation. In this research, we take three-dimensional ecological benefit assessment index of Taxus chinensis var. maire as a breakthrough point, and then we will get the purpose of controlling the macroscopic and using simple methods to manage the complex. These will make a solid foundation for scientific analysis, assessment and decision-making of Taxus chinensis var. Mairey of soil environment improvement and function of insect prevention.

References

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