Agroforest Syst (2015) 89:1019–1033 DOI 10.1007/s10457-015-9832-8 Intercropping teak (Tectona grandis) and maize (Zea mays): bioeconomic trade-off analysis of agroforestry management practices in Gunungkidul, West Java Ni’matul Khasanah . Aulia Perdana . Arif Rahmanullah . Gerhard Manurung . James M. Roshetko . Meine van Noordwijk Received: 1 June 2014 / Accepted: 24 July 2015 / Published online: 31 July 2015 Ó Springer Science+Business Media Dordrecht 2015 Abstract Producing high quality timber meeting 625 trees ha-1 (4 m 9 4 m)), thinning intensity (light export standards requires intensive tree management. (25 %), moderate (50 %) and heavy (75 %) of tree Using a tree-crop interactions model (WaNuLCAS) we density), and pruning intensity (40 % and 60 % of analyzed tree management practices in intercropped crown biomass). Cumulative maize yield in the first teak (Tectona grandis) and maize (Zea mays)compared 5 years of teak growth increased 10–38 % when tree to teak and maize monocultures. Tradeoff analysis in density was reduced. All simulated intercropping prac- intercropped teak and maize was designed in a three- tices produced a higher wood volume than a monocul- treatment factorial: initial teak density (1600 trees ha-1 ture, as trees benefit from crop fertilization. Maximum (2.5 m 9 2.5 m), 1111 trees ha-1 (3 m 9 3m)and wood volume (m3 ha-1) was obtained at initial tree density of 625 trees ha-1, 25 % of which was thinned in year 5 and another 25 % in year 15 with 40 % of the N. Khasanah (&) Á A. Perdana Á A. Rahmanullah Á crown pruned in years 4, 10 and 15. However, greater G. Manurung Á J. M. Roshetko Á M. van Noordwijk stem diameter as can be obtained with further thinning is Southeast Asia Regional Programme, World Agroforestry rewarded with higher market price per volume of wood. Centre (ICRAF), PO Box 161, Bogor 16001, Indonesia Profitability analysis taking into account the cost of e-mail: [email protected] labour (for maize production, thinning and pruning) and A. Perdana its effect on additional timber revenue showed that the e-mail: [email protected] highest net present value and return to labour was A. Rahmanullah provided by the system with 50 % thinning in year 5. e-mail: [email protected] Economic optimization was not sensitive to variations G. Manurung around the default price assumptions. e-mail: [email protected] J. M. Roshetko Keywords Agroforestry Á Ex-ante analysis Á e-mail: [email protected] Management practices Á Smallholder teak Á Trade-off M. van Noordwijk analysis e-mail: [email protected] N. Khasanah Jl. CIFOR, Situgede, Sindang Barang, Bogor 16115, Introduction Indonesia J. M. Roshetko Teak (Tectona grandis) provides high-value wood for Winrock International, Bogor, Indonesia furniture and other products. Asia holds more than 123 1020 Agroforest Syst (2015) 89:1019–1033 95 % of the world’s natural and planted teak were 45 % taller and 71 % larger than in monoculture resources, and more than 80 % of the world’s planted plot (Kumar et al. 1998). Intercropped teak - Salacca teak resources, with India (38 %), Indonesia (29 %) zalaca (Affendy et al. 2013), teak—sugar- and Myanmar (9 %) leading (Kollert and Cherubini cane/maize/cassava (Noda et al. 2012) can give a 2012). Indonesia, with its greatest production on Java, higher profit than monoculture teak. However, cumu- is the biggest teak sawn timber exporter in the world lative effect of the interactions between the various (Pandey and Brown 2000). Global demand for teak management practices affecting teak growth require wood has risen annually. FAO estimates demand for fine-tuning for specified climate and soil conditions of all types of wood has increased more than 50 % in a multiple combination of practices such as spacing, 15 years (FAO 2009). Historically export-quality teak pruning and thinning. The way tree and possible was primarily supplied by Perum Perhutani (Govern- intercrop growth is affected by such practices can be ment Forest Plantation Company), but their planta- tested directly in the field by establishing long-term tions can no longer guarantee sufficient teak wood multifactorial experiments, but this process requires a supply. Hence, smallholder teak growers have become lot of time, labour, and funds. Thus, bio-economic an important source of wood for the teak industry simulation models can help in pre-selecting candidate (Roshetko et al. 2013). management regimes for locally relevant conditions of A major challenge for smallholder teak growers is soil, climate, tree and crop properties, and prices for the production of high quality wood that meets export products, labour and inputs (Santos-Martin and van standards, as this generally requires intensive silvi- Noordwijk 2011). In weakly integrated bioeconomic cultural management. The lack of silvicultural man- models, economic analysis is conducted after biolog- agement, knowledge and skills linked to the prevailing ical results have been generated; in strongly integrated market incentive system is a key problem for small- bioeconomic models, economic decisions by man- holder producers (Roshetko and Manurung 2009). agers (farmers in our case) are represented by model Most teak growers continue to depend on natural parameters and included in the dynamic biological regeneration of their teak plantations. Weeding and model. An example of a strongly integrated bioeco- fertilizing are mainly carried out for the intercrops. nomic model is including the decision whether or not Most farmers do not practice thinning and pruning for to continue intercropping, based on information of the high productivity and quality of timber. Pruning is performance of previous crops, input costs, and market primarily conducted to collect fuel wood from prices. branches, rather than for controlling timber quality. The objective of this study was to explore growth Branches are cut, leaving 15-20 cm-long- branch and production of teak in smallholder systems with stubs. Thinning is considered as useless and even maize as intercrop under different tree management detrimental to teak stands and more likely to be carried practices in Gunungkidul, Central Java using the out on high grade timber, as farmers often cut the water, nutrient and light capture in agroforestry biggest tree to sell when they need the cash. But, along systems (WaNuLCAS) model, with direct bioeco- with participation of teak growers in various project- nomic feedbacks on crop decisions, and to evaluate its run silviculture activities, a better understanding on economy using profitability analysis. We chose maize the purpose of these treatments grew as part of a for intercropping as it is one of the main staple foods in recently completed project (Roshetko et al. 2013). the study area and it is also a recommended crop An extensive literature exists on optimum teak (besides groundnut and cassava) to be integrated in spacing (Ola-Adams 1990), effect of thinning (Kan- smallholder teak plantation. Specific objectives of the ninen et al. 2004; Perez and Kanninen 2005; Roshetko model study were: (1) to simulate growth interactions et al. 2013), effects of pruning (Viquez and Perez of teak—maize under different management options: 2005; Roshetko et al. 2013) and effects of intercrop- initial spacing, thinning, and pruning, (2) to analyze ping practices both on growth and profitability (Djag- the different management options from the biophys- bletey and Bredu 2007; Kumar et al. 1998; Affendy ical and economic prospective to identify the best and et al. 2013; Noda et al. 2012). However, results and the most profitable management practices for small- recommendations depend on context. Height and holder teak under local conditions, (3) to analyze diameter of teak growth in mixed plot with Leucaena sensitivity of the results under shifts in prices. 123 Agroforest Syst (2015) 89:1019–1033 1021 Materials and methods options separately from the model as a standalone ‘economic’ module was found to be efficient for further Brief description of WaNuLCAS model analysis of sensitivity to other economic input variables. Profitability analysis module inside WaNuLCAS model The WaNuLCAS, a tree-soil-crop interaction model is relatively simple as it translates current input and for agroforestry systems, was developed by the World labour use and products harvested into (discounted) Agroforestry Centre to deal with a wide range of economic performance indicators, which are used to agroforestry systems (van Noordwijk and Lusiana determine when to stop further intercropping. Further 1999; van Noordwijk et al. 2011). The model was post hoc economic analysis can be done in spreadsheets chosen for this study because it simulates dynamic using WaNuLCAS outputs. processes of above and below ground plant growth, The data used for model calibration and validation has the flexibility to represent tree– crop management was from experimental plots of smallholder timber options and direct economy-based farmer decisions trees (mixed systems of teak, acacia (Acacia man- regarding continuing or stopping intercropping. gium) and other species) in Wonosari, Gunungkidul, The model has spatial resolution at the plot scale, Central Java (Roshetko et al. 2013). Teak has been represented by a four-layer soil profile and four spatial successfully planted for the last 50 years to restore zones where trees and/or crops can be planted in any of degraded smallholder land in Gunungkidul. The teak the zones. The time resolution of the model is a daily was chosen by farmer as it is easily managed and can time step. The model takes into account three main be mixed with other trees and crop. However, component resources: light availability (for above- silvicultural management in the area are still limited. ground resource), water and nutrient (N and P) Hence the purpose of the experiment is to identify the availability (for belowground resources) that shared effects of various levels of pruning and thinning on by tree and crops based on above- and belowground productivity, growth and log quality of smallholder architecture and phenology.