Management plan for African mahogany

Management plan for African mahogany (Khaya senegalensis)

Abstract of a seminar presentation

Based on a hypothetically formed plantation company

Supun Nigamuni

Khaya senegalensis was introduced to Sri Lanka about 30 years ago and in the past 10 years it has become one of the priority species for timber plantation establishment in the dry zone. Timber is highly valued because of its beautiful figurative grain and its rich reddish mahogany brown colour. It is favored for furniture, high-class joinery, trim and boat building, railroad ties, flooring, turnery and decorative veneer.

A hypothetical company in the name of Greenwood Plantation Services Ltd was selected. Management objectives of the company are production of high-value; high-quality timber on sustainable basis to relieve the pressure on our valuable rainforests, practice commercial forestry by bringing in investors to invest in our plantations, achieve butt logs at harvest approximately 6 m in length and 40-60cm DBHOB with minimal taper and knots in 25 years, maintain plantation volume productivity, of 15-20 m³/ha/y merchantable volume over bark. Company is also aiming at achieving FSC certification enabling it to reach overseas markets.

A marginal land in the Dry Zone of 50 ha in Wellawaya is selected by using indigenous knowledge & checking soil parameters. Land Demarcation is carried out by surveying and establishing boundaries. Land is divided in to 10 perch blocks in order to attract small scale investors. Plots near the main roads or boundaries of the land and if there is a tank or natural scenery plots associated with that is kept by the company as a security. Main road of 20 ft, sub roads of 12 ft will also be demarcated. Land clearing, removing shrubs, clear debris is carried out in late September, holing & planting carried out in early October targeting the NE monsoon. 800-1100 trees/ha will be planted with a spacing of 3m × 3m. Live fire belt will be established using Hana.

Proper maintenance practices will be established including fertilizing up to 4 yrs and after the PCT with a mixture of N:P:K 9:13:9. Three commercial thinnings are carried out at the ages of 11yrs, 15yrs, 20yrs. Creeper cutting is carried out from the 1^st year while pruning carried out from 4^th year before and after the rainy season. Watering is done using drip irrigation up to 6 years, 4l/day in the dry season. Harvesting will be done using clear felling at the age of 25 yrs. In its natural range, K. senegalensis can be severely attacked by shoot borers (Hypsiphylla robusta). Such attacks may result in misshapen trees with no timber value. Carbofuran can be used to minimize these attacks.

At present harvest of 1 m³ of > 1.5m log in the local market is Rs. 13,830.00. Assuming 6% annual increase of Khaya lumber prices in 25 years it is projected to be Rs. 34,580.00. By doing a detail cost benefit analysis it is evident that the company will make an aggregate profit of Rs.1.4 billion in 25 yeas.

Establishment and maintenance plan for Pericopsis mooniana

Establishment and maintenance plan for Pericopsis mooniana

Abstract of a seminar presentation

Based on a hypothetically formed plantation company

Sarath Ranaweera

Pericopsis mooniana (Nedun) is a perennial tree of family Fabaceae. Mature height and dbh of this species are 20-30m and 30-70cm respectively. The trees are usually located in low land wet zone forests. Timber of Pericopsis mooniana works well with the tools. It has high durability. Colour of heart wood is dark brown and sap wood is pale in colour. It is good for furniture paneling, veneer and turnery production.

Nedun Plantation Company will start to establish a commercial Nedun plantation in June 2010. It is an investment company with Eco-friendly business plan. The company hopes to provide Nedun timber to local market and provide employment opportunities for rural people. For this proposes a land is selected in Karapagala, Mathugama. It is a barren one due to long term Tea cultivation, as well as due to high soil erosion.

The land should be developed using sloping agricultural land technique. Then Gliricidia is used to soil enhancement because it is a Nitrogen fixing and Nutrient recycling tree. Coir dust is applied as a mulch and Gliricidia shoots are lopped and laid on ground as twice per year. In addition to that Desmodium is planted as live mulch.

Nedun seedlings (purchased from FD) are planted in May-June of 2011 after totally killing of Desmodium using Glyphosate. Then Nedun and Pepper seedlings are planted. N.P.K. ratio (9:13:9) fertilizer is added to Nedun plants in first three years and just after PCT at year 7. Two pruning treatments must be done at age 4 and 7. Creeper cuttings are conducted twice per year until year 5. At pre-commercial thinning, 500 trees are removed at 7 years age. Pepper yield can be obtained from year 3 to year 13 of Nedun plant age. At year 13 of Nedun plants, 1^st commercial thinning is done to remove 300 trees. This practice cannot be done with Gliricidia and Pepper. Therefore they are removed before this thinning. Gliricidia timber can be sold as fire wood. After that, the 2^nd commercial thinning is done and sold as timber at 20 years age by removing 150 trees. We assume 0.3m³ volumes at 13 years, 0.5 m³ volume at 20 years and 1.0m³ volume at 40 years from a tree. Pest and diseases threats are minimal to Nedun plantation. Most of the time leaf eating caterpillars make damages. There is no severe damage after 3 years of Nedun plant. Therefore contact poisons can be applied within nursery period to first 3 years whenever necessary. There is a minimum threat to occur a forest fire, because this plantation is located in the wet zone. Most of the time surrounding people tend do illicit felling. Therefore the company expects to provide security using four watchers. One other benefit in addition to above of Pericopsis mooniana is that it can used to prevent soil erosion due to the heavy crown. It is also a carbon sink and create scenic value as a natural forest are more important through environmental view.

Establishment and maintenance plan for Cedrela toona

Establishment and maintenance plan for Cedrela toona

Abstract of a seminar presentation

Based on a hypothetically formed plantation company

Sadeepa Senarath Yapa

Establishment and maintenance plan for Cedrela toona is prepared by a company named as Evergreen Plantation Limited who is willing to establish a commercial toona plantation in a barren land of upcountry. The company is mainly targeting to obtain a maximum profit by selling toona timber which is popular as a veneer and used for decorative purposes.

This large tree species is a moderate shade demander whose best growth is at the elevation of around 1200m. As we have a barren land of 50ha with no shade trees we have planned to plant Acacia decurrens two years prior to planting toona in the spacing of 4.5m*4.5m. These Acacia plants will be removed completely form the site 7 years after planting them to provide more space for the growing of toona trees.

Land Preparation, planting and other treatments such as weeding, fertilizing, thinning, pruning and pest and disease control will be carried out in a very careful manner in order to obtain maximum volume of timber at the end of the rotation age of 30 years. Fencing and fire lining will be done in the early stages of the plantation establishment to prevent manmade and natural damages to the plantation.

Final stock will be 225 trees per ha which will be removed by shelter wood system to minimize environmental damages which can be occurred in clear felling. Selected trees will be felled, extracted the moved to roadside and transported to the local market.

Effect of farmer woodlots on farmers

Evaluation of farmers woodlots in the aspects of growth and effect on farmers

Thilina Jayarathne and Upul Subasinghe

Paper presented for the 14th International Forestry and Environmental Symposium 2009

The total forest cover of Sri Lanka is estimated as 32% from the total land area. More than 50% of this area lies in the dry zone where the original forests have been cleared drastically. Plantation forests are therefore being established particularly with exotics as local species are very slow growing, despite their very high timber value. Teak was the first exotic species introduced to Sri Lanka by Dutch in the 17th century for replanting purpose. Other than planting by Forest Department of Sri Lanka, the other methods of establishing teak plantations were community forestry projects (CFP), and now by participatory forestry projects (PFP).

The objective of the present study was to evaluate the farmers' woodlot programmes to identify the effects on farmers. For this purpose, a questionnaire survey was conducted to obtain information on their socio-economic status and management constraints from Anuradhapura, Thambuttegama, Kekirawa Ranges (Anuradhapura Forest Division), Habarana Range (Polonnaruwa Forest Division) and Galgamuawa Range (Kurunegala Forest Division). The questionnaire was distributed among randomly selected ten farmers of each plantation (altogether 214 plantations).

The results revealed the inadequacy of current lease agreement (25 years) and 100% of the respondents wanted to have an extension varying from 5 to 50 years. Moreover, 98% of the total respondents agreed to implement this programme for a second rotation. Farmers have been given a proper guidance by the government officers during the initial establishment stage of the farmer's woodlots. However, it has become inadequate with the time, especially when pruning and thinning are required. Elephant's damages and lack of water are the major problems faced by the most of the farmers. However, according to the farmers, there were minimum elephant damage after plantations become naturalised as witnessed in the Rambukwewa plantation in the Kekirawa range.

Results and direct observations also indicated that some lands given to establish farmers' woodlots are marginal lands for plant growth. Most of lands also indicated frequent fire and erosion. Since teak needs comparatively more nutrients for plant growth, it is recommended to evaluate the chosen sites for (i) the available nutrient levels, (ii) required timber species to match the site quality and (iii) the required growth rate.

In order to enhance the income of the farmers, it is recommended to start the second cycle of woodlots soon after completing the present one, perhaps with better management techniques. However, the plantations vulnerable for elephant damages should not be replanted using teak unless there is an effective protection system. Otherwise such plantations should gradually be converted to natural dry zone forests by the local species such as Azadirachta indica and Tamarindus indica.

Timber production in high density planting of Rubber

Timber production in high density planting of Hevea brasiliensis (Rubber)

Kelum Silva, Upul Subasinghe and Lakshman Rodrigo

Paper presented for the 14th International Forestry and Environmental Symposium 2009

The demand of natural rubber has increased continuously with the increase of population and living standards of the human being. Rubber plantations are also a major source of timber and fuels wood. In order to meet the continuous increase in demand for latex, timber and fuelwood, the productivity of rubber plantations should be increased. Whilst producing high yielding clones for improved latex and timber yield per tree which is a long-term process in perennial crops, planting density could be adjusted to obtain high productivity in rubber plantations. The present level of planting density of rubber in Sri Lanka has been decided on the experiments conducted with the genotypes which are not in common use at the moment. Therefore the present study was aimed to identify the suitable planting density for the recently developed and commonly used genotypes of rubber. This paper is focused to assess the timber production of rubber with respect to high density planting.

The experiment was set up in Rathnapura District of Sri Lanka in 1992. Rubber was planted in three high densities, i.e., 600, 700 and 800 trees per hectare. Also three genotypes (clones), i.e., RRIC 100, RRIC 110 and RRIC 121 were incorporated with the statistical design of split plot where the planting densities were laid as the main plot whilst clones were in the sub-plots. Five trees in each sub-plot were randomly selected and used for the measurements of total tree height (TH), crown height (CH), thickness of the untapped bark (BT) and tree diameter at breast height. Thereafter, stem volumes were determined using the Newton’s formula.

Both TH and CH did not vary significantly among the planting densities tested. Although not statistically significant, there was a marginal decrease in tree diameter with the increase in planting density. Irrespective of the clone used, BT and mean merchantable timber volume per tree decreased significantly with increase in planting density. Nevertheless, this decrease was compensated by the increased number of trees in high densities resulting in comparable level of merchantable volume per hectare among different densities. Total stem volume per tree remained same among four densities tested with that total stem per hectare increased significantly with the increase of planting density. Therefore, higher densities are more useful in the industries of fuelwood, pulp, MDF boards etc. Among the clones tested, the clone RRIC 212outperformed in growth and timber production. The clone RRIC 110 was infected with the Corynespora disease hence showed poor performance in all densities. Despite the increase in total timber production with the increase in planting density, overall financial viability of different densities is to be assessed considering all cost components and valuing both timber and latex produced before making any firm recommendation.

Establishment of relationships of growth at 7-year old mahogany trees with selected site factors

Establishment of relationships of growth at 7-year old mahogany trees with selected site factors in low country wet zone, using GIS as a tool

Himesha Randeni and Upul Subasinghe

Paper presented for the 14th International Forestry and Environment Symposium 2009

Mahogany (Swietenia macrophylla) is an exotic tree, which is heavily adapted to the climatic conditions of wet and intermediate zones of Sri Lanka. Although the state sector manages mahogany with longer rotations, private sector expects to achieve the maximum timber yield within a shorter period. Due to the land scarcity, many of these mahogany plantations have been established in barren and rubber uprooted lands which were heavily degraded. Therefore the soil conditions and site factors directly affect the growth of the mahogany within short rotations.

The present study was carried out in a 7 years old mahogany monoculture plantation established in Gomaragala, in low country wet zone of Sri Lanka to find out the effect of soil and site factors to the mahogany tree growth. Extent of this forest is 20.7 ha and it is managed by a private plantation company. This forest has been divided into 2 lots for the purpose of administration and further divided into 240 plots of 20 perch each.

In order to identify the relationships, tree dbh and height were used as growth parameters. Slope, bedrock establishment and terrain were selected as selected site factors. The growth parameters (i.e.dbh and height) were measured for all the trees in plantation (one measurement from each plot). Slope and terrain as geographical parameters were measured of all 240 plots in the entire plantation.

Since the regression based methods were not adequate for both qualitative as well as quantitative parameter analysis, GIS based analysis was decided to use for the present study, using ArcView 3.3. In order to create digital maps, the survey plan of the selected forest was digitized and georeferanced using 10 ground control points collected by a GPS data receptor. Then the georeferanced base map was digitized to demarcate all the plots and other land marks. After that different maps were prepared in vector form separately for each parameter. However, for the analysis, all these vector layers were converted to raster layers. Raster layers were then reclassified and overlaid two or three layers at a time with the growth parameters to identify the effects. Then map analysis was completed to make decisions regarding tree growth in different site factors.

Results revealed that there are significant relationships between tree growth and the selected site parameters. However, the best conditions for the mahogany tree growth in the particular area are the slope between 11⁰-24⁰, and shallow bedrock prevalence and stony terrain.

Change of crown diameter with dbh of mahogany

Change of crown diameter with dbh of Swietenia macrophylla (mahogany)

even-aged monocultures

Shanika Lakmali and Upul Subasinghe

Paper presented for the 14th International Forestry and Environment Symposium 2009

Mahogany is one of the renowned timber species for its beautifully grained, hard and red-brown wood. It is an introduced timber species, dominated in Sri Lankan forest plantations with fast growth rates and higher timber value. Mahogany plantations are widely established in the intermediate zone and low country wet zone in Sri Lanka. Recently, private sector has started to establish of mahogany monocultures with shorter rotations to gain high income.

Due to the lack of research studies on mahogany, the objective of the present study was to establish an empirical model to predict crown diameter accurately using dbh. For this purpose, data were collected from 16 mahogany monocultures in Kalutara, Ratnapura and Matale districts. In order to represent the whole plantation, sixty trees were selected from good, moderate and poor areas from each plantation.

In order to build a reliable model, theoretical basic structures were developed assuming the crown diameter is a function of tree dbh. This basic structure was fitted to the data as linear, exponential, and logistic form separately for different growth types. In addition to the untransformed variables, transformations were also made whenever possible. Suitable candidate models were preliminary selected by R2 and residual distributions. After further analysis, it was proven that the best results were given by the logistic model structure for good, moderate and poor site types (R2 = 92.0%, 71.4%, 65.9% respectively). In order to eliminate the difficulty of using separate models for different growth types, the possibility of using a common model for all growth types were tested. For this reason, one way ANOVA was used for residuals of different growth types generated after fitting respective models. Results indicated that it was possible to use a common model and therefore the logistic form was re-fitted to pooled data.

The final model was “crown diameter = 0.645 + 2.682 / (1+exp (-0.356 (dbh –7.749)))” and it had a R2 of 60.9%.