Tài liệu ABOVEGROUND CARBON STOCK ESTIMATES OF RUBBER (Hevea brasiliensis) PLANTATION AT MAKILING FOREST RESERVE doc

* Associate Professor, Institute of Renewable Natural Resources IRNR, College of Forestry and Natural Resources CFNR, University of the Philippines Los Banos**Assistant Professor, Depart

* Associate Professor, Institute of Renewable Natural Resources (IRNR), College of Forestry and Natural Resources (CFNR), University of the Philippines Los Banos

**Assistant Professor, Department of Forestry and Environmental Science, College of Agriculture and Forestry, Bohol Island State University (BISU), Bilar, Bohol

ABOVEGROUND CARBON STOCK ESTIMATES OF

RUBBER (Hevea brasiliensis) PLANTATION

AT MAKILING FOREST RESERVE

ARTURO SA CASTILLO* and TOMAS D REYES, JR.**

Climate change is one of the primary concerns of humanity today (Lasco et al 2002)

other land uses every year

In fact, according to FAO (2003), 23,260 km2 of forests are destroyed per year in Southeast Asia Problems leading to

poverty rise are even exacerbated by human-aggravated

natural disasters

Plantations intended, not for timber but, for other purposessuch as fruits and seed sources, and other non-timberproducts (one of which is latex production) have valuable role

in relation to climate change

Similar with the forests, plantations can be sources and sinks

of carbon Its non-use value, carbon sequestration for

instance, sometimes outweighs natural forests

Much of the carbon sequestration, according to Lasco and Pulhin (2003), is attributed to the existence of tree plantations with a sequestration rate of up to 15 t ha-1 yr-1

This study was conducted to determine the immensepotential of rubber plantations in sequestering carbon in theMFR aside from the very purpose of establishing thisplantation for latex and other uses.

Specifically, it provided calculation of the amount of

secondary data, and the assessment of the condition of thesite

A nation-wide study is recommended to determine, quantifyand value the potential environmental-social contributions andbenefits of existing rubber plantations in the Philippines tomitigate climate change

Study Site

Rubber (Hevea brasiliensis) plantation in Mt Makiling was

established in 1961

Located in Zone 6 of Makiling Forest Reserve (MFR)

14.08 hectares (Almazan et al 2000), which now totaled to

16 hectares after a series of replanting and expansion

Type 1 climate, annual rainfall ranges from 2,481 to 2,681

temperature ranges from 25.5 C to 27.5 C

Soil types belong to four series: Macolod, Lipa, Gulugod, and Makiling; Clay to silt loam

Topography - slightly rolling to rolling with 10-30% slope

The area is approximately 199 meters above sea level and lies in the mid-slope of Mt Makiling facing the

southeast orientation

Composed mostly of rubber with 99 other forest tree

species (Almazan et al 2000)

Biomeasurement and Plantation Assessment

The 14-ha Hevea Plantation of Mt Makiling Forest

composition and forest structure on January 2010–March2010

height, total height, and others) and understorey vegetationwere recorded down to species level

In the established 50 (100 sq meters) plots, a total of 23species of trees belonging to 19 genera, under 12 familieswere identified.

Fifty (50) understorey species in 43 genera and 21 familieswere also recorded (Reyes, et al 2010)

Visual assessment was also conducted to evaluate thecondition of the rubber trees and the whole plantation

Standard volume formula:

Volume (m3) = ∏r2*L = ∏(d/2)2*L = 0.7854*(DBH in cm)2*(MH

in m)

Allometric equations (Brown, 1997 and Brown et al 1989):

For DBH limit < 60 cm and an annual rainfall ranging from1,500-4,000 mm (with r2 = 0.97)

2.530*LN(DBH)}

For DBH limit 60 – 148 cm and an annual rainfall ranging from1,500-4,000 mm (with r2 = 0.84)

RESULTS AND DISCUSSION

Tree Biomass (in cubic meters)

The tree biomass for the whole plantation was computed

to be 6,486.14 m3 This value came from the 231.65 m3 of

each) systematically laid in the plantation

Tree species which contributed much biomass in the

plantation were rubber (Hevea brasiliensis) and mahogany

129.50 m3 (27.95%), respectively

Species Common Name Scientific Name Density (m 3 /ha)

Rubber Hevea brasiliensis 166.40 Big-leafed Mahogany *Swietenia macrophylla 129.47

Igyo Dysoxylum gaudichaudianum 30.41

Alupag Litchi chinensis philippinensis 1.41

Tuai Bischofia javanica 0.06

Note: Trees with asterisk (*) are considered invasive – exotic species

Table 1 List of trees and their corresponding volume (m 3 ) per hectare

Tree Biomass and Carbon Estimates (in tons)

Estimated total aboveground biomass production for thewhole plantation was 7,030.51 tons That was about 502.18tons per hectare

Its carbon content per hectare basis, following theconservative estimate of about 45% (Lasco, et al 2003), wascalculated to be 225.98 tons, giving a total carbon of about3,163.73 tons

Over thirty-five per cent (35.92%) of the total computed

carbon was attributed to H brasiliensis trees which

dominated the site (being the desired crop) for almost 4decades

Species Scientific Name Biomass (ton/ha) Carbon (ton/ha)

Rubber Hevea brasiliensis 185.60 83.52

Big-leafed Mahogany *Swietenia macrophylla 153.23 68.95

Rarang Erythrina subumbrans 39.74 17.88

Igyo Dysoxylum gaudichaudianum 25.58 11.51

Palosanto *Triplaris cumingiana 20.09 9.04

Amuyong Goniothalamus amuyon 6.81 3.07

Bagtikan Parashorea malaanonan 6.13 2.76

Banuyo Wallaceodendron celebicum 5.86 2.64

Binuang Octomeles sumatrana 4.65 2.09

Amugis Koordersiodendron pinnatum 4.48 2.02

Ilang-ilang Cananga odorata 4.24 1.91

Kalomata Clausena brevistyla 1.80 0.81

Alupag Litchi chinensis philippinensis 1.51 0.68

Antipolo Artocarpus blancoi 0.81 0.37

Basikong Ficus botryocarpa 0.48 0.22

Hamindang Macaranga bicolor 0.36 0.16

Anuling Pisonia umbellifera 0.19 0.08

Miscellaneous (unidentified) 0.19 0.08

Upling gubat Ficus ampelas 0.10 0.05

Santol Sandoricum koetjape 0.10 0.04

Tuai Bischofia javanica 0.08 0.04

Katap Trigonostemon acuminatus 0.08 0.04

Table 2 List of tree species with corresponding estimated biomass and carbon content (t ha -1 )

Note: Trees with asterisk (*) are considered invasive – exotic species.

Rubber plantation plays an important role with regard tocarbon contribution to the environment.

A 27-year old stand of rubber trees in Malaysia had a totalamount of carbon stock of about 319 tC ha-1 (Sivakumaran et

al 1992 cited by Chung 2004)

In addition, the biomass potential of another 33 year oldstand was recorded to be 444.9 t ha-1 This value is close tothose obtained for forest ecosystems in Brazil and Malaysia,

or even higher than those recorded in Thailand and NewGuinea (K Sivanadyan and Norhayati, 1992 cited by Chung2004)

The relatively high aboveground (tree) carbon content inthe study site (MFR Rubber Plantation) is due to the fact that

Hevea, and perhaps Swietenia, are very efficient inconverting solar energy into dry matter

This holds the same observation with the work of Chung(2004) According to Templeton (1969) cited by Chung(2004), the rate of dry matter production of 5 ¼ and 6 ¾ years

stand of Hevea was 35.5 tons h-1 yr-1, a relatively high valueamong tree species He also added that at this rate of drymatter production, the efficiency of utilization of solar

radiation in a stand of Hevea trees with a closed canopy was

calculated to be about 2.8%

Naimah, Zainol and Yoon (1992) cited by Chung (2004) also

reported that Hevea trees have the highest photosynthetic

productivity and with a capacity to fix 90 million tC yr-1

Though the results above are exceptional case for Hevea

plantation, this estimated aboveground (tree) biomass perhectare computed was a bit below the estimated biomass of

Swietenia-dominated plantations (Racelis 2000, Lasco et al.

2001), dipterocarps (Racelis 2000), and tree legumes (Lasco

et al 2001) in Mt Makiling

This could be because the plantations mentioned wereestablished a couple of years earlier than the rubberplantation, and these plantations (especially the first two) arecomposed of trees of much bigger stature

Results of the study further showed that rubber plantationexhibited lower tree carbon content compared to a naturalforest, a secondary forest, and some fast growing plantationsbased on previous studies conducted in the country (Lascoand Pulhin 2003)

Plantation Assessment

Only about 20.16% of rubber trees was found in good

quality state Most of them were noted crooked and leaning (70.93%)

The density of rubber per hectare was computed 258,

while mahogany had 158 individuals Other tree species

were counted not more than 50 individuals per hectare each

Huge crown of mahogany also restricted solar radiation to reach the forest floor which limits the germination of seeds and the growth of rubber seedlings

Common

Tree Species

Density (#/ha)

Area (m 2 /ha)

The potential of a system to sequester carbon is alsoaffected by its physiological and environmental conditions.

The above result shows that there is a greater possibility that

a plantation forest can attain or even surpass the capacity of anatural forest to store carbon and more than the other forestecosystems

Factors can be attributed to this are good site conditions,proper silvicultural treatments, level of utilization, and humandisturbance

The same can be attributed to allowing that stand to attainits optimum growth or leaving the stand to reach its fullmaturity (Racelis, 2000)

CONCLUSIONS

Examined some gray areas.

Include the bio-measurements of other carbon pools

which were not considered in this study

Specific allometric equations should also be generated following the guidelines

Adequate number of permanent plots within the plantation should be established

RECOMMENDATIONS

Determine the effectiveness of tree plantations insequestering carbon, aside from knowing the biomass vis-à-

sequestration rates, the period at which C sequestrationrates are at maximum; age, and the C pools and fluxes interms of species and locality

Investigate how to maximize the rate of accumulation ofatmospheric carbon in rubber plantation in terms of effects ofsilvicultural treatments/practices like cultivation, weeding,fertilization, thinning, among others

The authors would like to thank Leonardo Lapie, Archibald Baltazar Malaki, Roy Joven Amatus, Russel Son Cosico, and Leyminda Maranon, all graduate students, who helped in the conduct of data collection.