Growths and Carbon Stocks of Para Rubber Plantations on Phonpisai Soil Series in Northeastern Thailand

RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com Growths and Carbon Stocks of Para Rubber Plantations on Phonpisai Soil Series in Northeastern Thailand Chakarn Saengruksawong Soontorn Khamyong, Niwat Anongrak, Jitti Pinthong Department of Plant Science and Natural Resources, Faculty of Agriculture Institution: Chiang Mai University ABSTRACT ARTICLE INFO Article history: Revise: 1 January 2012 Revise: in revise Presentation of IRRDB Conference, 15-16 December 2011, Chiangmai, Thailand Accepted: 12 January 2012 Available online: 15 January 2012 Keywords: carbon stock, rubber growth, rubber plantation, biomass, Chakkarat soil series Growths and carbon stocks in a series of para rubber plantations on Chakkarat soil series in northeastern Thailand were investigated including 1, 5, 10, 15 and 20 years old, and a natural forest. Totally 15, 40 x 40 m sampling plots were used for studying rubber growths, three plots per each aged class plantation and one plot for the natural forest. In each plot, stem girth at 1.3 m above ground, crown width and height of trees were measured. One rubber tree having the mean growth in each aged class plantation was cut and separated to stem, branch, leaf and root biomass for making allometry equations. Fifteen soil pits were made in each plot, and soil samples were collected along soil profile. Soil physical and chemical properties were analyzed in laboratory. Rubber tree densities varied between 80-109 trees/rai (1ha = 6.25 rai). Stem girth and height growths were increased with the plantation ages. The growths were very rapid for rubber trees having ages between 1 and 15 years old and become slow for the older trees. The biomass amounts of 1, 5, 10, 15 and 20 years old plantations were in the order of 21.25, 55.24, 102.39, 140.50 and 215.39 Mg/ha. Ecosystem carbon stocks in these plantations were increased with tree ages as 26.29, 48.28, 76.62, 95.83 and 135.38 Mg/ha, respectively. They involved two compartments; (1) biomass carbon: 12.03, 31.45, 58.10, 79.78 and 122.01 Mg/ha; and (2) soil carbon: 14.26, 16.83, 18.52, 16.05 and 13.37 Mg/ha. The total carbon storage in natural forest was 134.62 Mg/ha; 124.20 Mg/ha in biomass and 10.42 Mg/ha in soil. The young plantations had the high carbon percentages in soil and low in biomass whereas carbon allocation in the older plantations was higher in biomass and lower in soil system. RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com Introduction Thailand is the world leading producer and exporter of para rubber (herein called rubber) with production capacity of 3.1 – 3.2 million tons per year, with 88-90 percent of total production capacity exported to foreign markets. The country also has high potential for expanding production area and raising production capacity. In year 2009, rubber plantations in Thailand covered 2.70 million ha across Thailand with the majority (2.10 million ha) in the traditional areas in the southern (2.61 million ha) and eastern 14.68 million ha) region and the remaining 0.60 million ha are planted in new areas in the northeastern (0.45 million ha), northern (0.09 million ha) and central (0.05 million ha) region. The northeastern region of Thailand has agricultural area of 15.90 million ha, of which 6.65 million ha are suitable for rubber plantation. However, only 3.09 million ha, have yield more than 1,562 kilogram per ha per year and currently 0.45 million ha are being used for rubber plantation. The remaining 2.65 million ha, an area equal of total area being for rubber production today, is still available for additional rubber production. Hence, northeastern region of Thailand will be an important rubber production source for Thailand in the future. Global warming is a present problem and spreading throughout the world, encouraging all nations to take various measures to reduce global warming under the KYOTO protocol. The protocol is a part of the United Nations Framework Convention on Climate Change (UNFCC), enforced in 2005. Even if Thailand is a non-annex 1 member country that can reduce greenhouse gas emission through the clean development mechanism, the appropriate approach is to plant para rubber plantation in place of deforestation in Thailand. Because rubber trees have production life of 20 years, the plantation can be considered as forest plantation as rubber tress increase in biological mass as they age and has high capacity for carbon stock storage. Development of northeastern region as part of the country’s rubber production source will need a study on environmental affect on growth pattern in different areas of the region, especially rainwater, humidity, soil characteristic and rock formation. Different soil qualities have strong affect to the debt of water drainable, physical, chemical and biological properties (Bowen & Nambiar, 1989; Fisher & Binkley, 2000). It will also influence the amount of carbon stock stored in different age group of rubber trees hence will affect the environmental role of rubber plantation and will be an important data for better management at relevant organizations. Nongkhai Province has plantation area of 724,590 ha with areas suitable for rubber plantation of 340,606 ha. It is also the province with most area used for rubber plantation in its region, coving 102,051 ha and also has remaining potential land use of 238,3994 ha. Moreover, it is the first test province with pilot plantation project by the Rubber Research Institute of Thailand (RRIT) in year 1978, giving it many test plantation aging from 1 year old to 20 years old. Investigation from the Land Development Department shows that most soil type found in the area is the Phonpisai soil coveringin 153,410 ha. Studies on the growth pattern, bio-productivity, and carbon stock potential on Phonpisai soil type is an interesting topic and will provide important data for the development of management and encouragement of appropriate rubber plantation that give high yields and rehabilitate the environment. Methods Research site The research site is located in Rattanawapi District and Phonpisai District, Nong Khai Province. The site is located between latitude 17degrees 52 minutes north and longitude 102 degrees 44 minutes east. The land elevation from normal sea level sits between 161-200 meters with incline of 1-7%. 2 RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com Growth and biomass of rubber Three samples are selected from five different age groups of plantations including 1 year, 5 years, 10 years, 15 years and 20 years old that are 40 x 40 square meters in size. Growth studies are done by measurements of the tree circumference at height of 130 centimeters from the ground as well as measuring the total height of the tree itself. Biomass measure for the tree in each age group are determined by cutting trees with similar size and height to the average tree in each plantation, one for each age group. Samples trees are then divided into trunk, branch, leaves and roots for analysis between biomass and D2H to determine the carbon in each part of the tree as well as the entire carbon stock. Growth of plant species and biomass in referenced natural forest Research samples are selected from sample sites in natural forest of Phonpisai District that are in close proximity to pilot plantation. Natural forests in the area consist of dipterocarp forest size of 40 x 40 square meters measuring tree diameter at 130 centimeter height as well as plant species with height of over 1.50 meters. The quantitative calculations of each plant species include the density, important distinction and indicators. Qualitative biodiversity data includes listing names of plant species in the area in both common and scientific names and calculation the biomass of plant species with the following formula Ogino et al. (1967) W (trunk) = 189 (D2H)0.902 W (branhc) = 0.125 W 1.024 1/WL (leaves) = (1/WS0.9) + 0.172 when W = biomass (kilograms per hectare) D= diameterat1.3 meters from ground (meters) H = tree height (meters) Soil characteristics, carbon stocks and nutrition Soil studies affecting rubber and plant species growth in sample plantations and natural forests are conducted by digging for three sample soils in plantations aged 1, 5, 10, 15 and 20 years old as well as one sample soil in natural forests, totaling 16 dig sites. Each dig sites are 1.5 meters wide, 2.0 meters long and 1.2 meters deep. Studies and analysis on soil characteristic are done by studying the physical and chemical properties of the soil. Physical properties studied includes (1) total soil density of the soil through the core method, (2) gravel quantity for size more than 2 mm by weighting method, and (3) particle-size distribution and soil texture by hydrometer method. Chemical property studied includes (1) soil reaction by pH meter method in ratio of 1:1 with water, (2) carbon exchange capcity (CEC), (3) total nitrogen by micro Kjedahl method, (4) organic matter and carbon in soil by wet oxidation method of Walkley and Black (Nelson and Sommers, 1982), (5) useful phosphorous concentration by Bray II and colorimetric method, (6) useful potassium level by extracting with ammonium acetate 1N, pH 7.0 and measured by flame photometer and (7) calcium and magnesium concentration extracted with ammonium acitate 1 N, pH 7.0 and measured by atomic absorption tool. Calculations of carbon level in soil from soil mass and carbon concentration fluctuation in each soil level were also conducted. Results and Discussion Growths Growth of rubber consists of the diameter, height and bush size which will differentiate between age groups. Table 1 shows the growth of rubber tree in each age group. It is found that the density of the rubber tree varies a little. The density of age groups 1, 5, 10, 15 and 20 years old averages at 78, 71, 79, 81 and 85 respectively. The circumference of the tree increases as the tree age. Trees aged 1, 5, 10, 15 and 20 years old have average circumference of 8.23, 29.42, 36.76, 53.54 and 54.45 respectively. The average heights are 6.49, 8.83, 11.98, 15.41 and 14.46 centimeter and bush sizes of 2.60, 3 RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com 4.80, 5.30, 6.40 and 5.70 centimeters respectively. As for the amount of rubber tree that can be harvested according to recommendations of the RRIT, it is found that 5 years old plantations do not have trees with circumference higher than 50 centimeters, the size appropriate for harvesting. Only 1.69% of 10 years old trees have circumference measurement higher than 50 centimeters. The ratio increases to 65.88% and 67.45% for 15 and 20 years old plantations respectively. For the diameter of the trees, the standard used for rubber wood purchases, it is found that pilot plantations have diameters of 6 inches or more for 10 years old plantations. However, only 5.91% of 10 years old tress have diameter more than 6 inches and increases to 53.31% and 56.86% for 15 and 20 years old plantations respectively. Compared to southern rubber plantations, the circumference, diameter and ratio of harvest-read samples of the rubber trees in the northeastern region is lower. This is due to the lower fertility of the soil in the northeastern region. As for the height and branching level comparison with the southern region, pilot plantations in the northeastern region are similar to that of the southern region for the same age groups. Biomass Average biomass for the pilot plantation in each age group from 1, 5, 10, 15 and 20 years old equals to 3.2, 43.0, 94.5, 278.8 and 264.9 kilograms per tree respectively. Table 2 shows the biomass per area with plantations aging 1, 5, 10, 15 and 20 years old having total biomass of 1.54, 19.10, 46.66, 140.56 and 140.73 Mg/ha respectively. 1 year old plantation has average biomass of 1.54 Mg/ha Biomass from trunk, branch, leaves and roots equal 0.63, 0.13, 0.25 and 0.52 Mg/ha respectively, calculated into a ratio of 37.07, 30.13, 6.69 and 26.15 percent respectively. 5 years old plantation has average biomass of 19.10 Mg/ha Biomass from trunk, branch, leaves and roots equal 7.07, 5.75, 1.28 and5.00 Mg/ha respectively, calculated into a ratio of 40.84, 8.73, 16.41 and 34.02 percent respectively. 10 years old plantation has average biomass of 46.66 Mg/ha Biomass from trunk, branch, leaves and roots equal 15.43, 18.59, 2.23and10.41 Mg/ha respectively, calculated into a ratio of 33.07, 39.84, 4.67 and22.30 percent respectively. 15 years old plantation has average biomass of 140.56 Mg/ha Biomass from trunk, branch, leaves and roots equal 39.01, 72.50, 4.31 and 2.49 Mg/ha respectively, calculated into a ratio of 27.29, 52.37, 2.97 and 17.36 percent respectively. 20 years old plantation has average biomass of 140.73 Mg/ha Biomass from trunk, branch, leaves and roots equal 39.01, 72.50, 4.31 และ 2.49 Mg/ha respectively, calculated into a ratio of 27.72, 51.52, 3.06 and 17.70 percent respectively. Biomass of rubber trees increases as they age with very fast rate from 1 to 15 years old and slows down during 15 to 20 years old. The ratio of biomass accumulation in each part of the tree also changes as they age. In plantation aged 1, 5, 10, 15 and 20 years old, the ratio of biomass accumulation compared to the total biomass equals to 40.84, 37.03, 33.07, 27.29 and 27.72 respectively. The ratio for the branch increases as the tree age, from 8.73 to 30.13, 39.84, 52.37 and 52.52 percent respectively. In contrast, the ratio for the leaves and roots decreases. 4 RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com Fig. 1. Stem girth and height growths, and biomass of para rubber in 1-, 5-, 10-, 15- and 20-year-old plantations on Phonpisai soil series Ponpisai Ponpisai 100 90 80 70 60 Rep.1 50 Rep.2 40 Rep.3 30 20 10 0 1 5 10 15 20 30 25 20 Rep.1 15 Rep.2 Rep.3 10 5 0 1 5 10 15 20 Plantation ages (years) Plantation ages (years) Ponpisai 40,000 35,000 30,000 25,000 Rep.1 20,000 Rep.2 15,000 Rep.3 10,000 5,000 0 1 5 10 15 20 Plantation ages (years) Table 1. Growths and biomass of para rubber in different age plantations on Phonpisai soil series Plantation Plot age (years) No. 1 1 2 3 Mean 5 1 2 3 Mean 10 1 2 3 Mean 15 1 2 3 Mean 20 1 2 3 Mean Density (trees/rai) 79 78 77 78 71 71 71 213 80 79 78 237 86 77 79 242 85 86 84 255 GBH (cm) 8.86 + 1.97 7.69 + 1.56 8.13 + 2.22 8.23 + 1.99 31.92 + 4.86 30.86 + 5.33 25.50 + 5.39 29.42+ 5.89 34.79 + 9.12 34.60 + 6.66 40.96 + 7.23 36.76 + 8.26 50.92 + 10.63 52.23 + 11.77 57.67 + 11.25 53.54 + 11.54 54.90 + 11.20 53.05 + 8.89 55.44 + 10.65 54.45 + 10.30 Height (m) 6.57 + 0.83 6.53 + 0.69 6.36 + 0.70 6.49 + 0.75 8.86 + 0.30 8.84 + 0.39 8.78 + 0.41 8.83 + 0.37 12.04 + 1.45 12.03 + 1.26 11.87 + 1.17 11.98 + 1.30 15.34 + 0.93 15.34 + 0.66 15.55 + 0.61 15.41 + 0.76 15.07 + 1.58 14.22 + 1.18 14.08 + 1.14 14.46 + 1.38 Crown width (m) 2.70 + 0.20 2.60 + 0.20 2.60 + 0.20 2.60 + 0.20 5.10 + 0.80 5.20 + 0.80 4.10 + 0.80 4.80 + 0.90 4.80 + 0.60 5.20 + 0.80 5.90 + 0.60 5.30 + 0.80 6.60 + 1.60 7.20 + 1.50 6.40 + 1.60 5.70 + 1.60 5.70 + 1.40 5.70 + 1.40 5.70 + 1.40 5.70 + 1.40 Biomass (kg/tree) 3.6 2.8 3.1 3.2 50.0 46.8 33.3 43.0 87.6 81.7 114.5 94.5 246.7 263.4 328.7 278.8 284.1 244.1 266.8 264.9 5 ... - tailieumienphi.vn