Fertilizer requirements of newly established plantations of some timber and lesser-used species

Some of the timber and lesser-used tree species found in the Ilocos Region [Philippines] includes 'supa' (Sindora supa), 'dao' (Dracontomelon dao), 'panglomboien' (Suzyguim simile), 'piling-liitan' (Canarium luzonicum), 'bangkal' (Nuclea orientalis), 'kariskis' (Albizia lebbekoidez), 'sakat' (Terminalia nitens), and 'banaba' (Lagerstroemia speciosa). Dao and supa are considered premium tree species because these produce high quality wood for construction and furniture making. On the other hand, the latter six species are considered lesser-used tree species because these are not used in industries or traded in commercial scale. Nevertheless, these are considered multiple tree species because of their many uses. Rural folks use them in the construction of their houses and farm structures and in making or replacing worn-out parts of farm implements. These are among the priority species identified by the DENR for reforestation activities in Region I [Ilocos Region, Philippines]. Rosario et al. (MMSU) evaluated the effects of different types and rates of fertilizers on the growth and survival of the above mentioned timber and lesser-used species in 2005-2006. The types of fertilizer used were complete, mykovam, urea, and organic while the rates of the treatment were 20g, 40 g, and 60 g for complete; 20 g for urea; 20 g and 40 g for both organic and mycovam. Findings of the study include the following: Banaba and pangloboien had the highest height increment (26.3 cm and 44.9 cm, respectively) with 60 g complete fertilizer. The lowest height increments were observed in banaba seedlings fertilized with 40 g mykovam and 20 g urea (8.5 cm and 10.9 cm, respectively) and the unfertilized panglomboien (21.9 cm). The fastest height growth was observed in bangkal treated with 40 g and 60 g complete fertilizer (34.8 cm and 35.2 cm, respectively), while kariskis and sakat fertilized with 40 g complete had their highest height increment at 22.5 cm and 39.8 cm, respectively. Bangkal and kariskis kad their lowest height increment (20.9 cm and 7.9 cm, respectively) when unfertilized. A slightly different result was observed in dao, wherein its seedlings' highest height growth was achieved with 20 g urea, 20 g complete, and 40 g organic fertilizer applications (18.3 cm, 17.7 cm, and 17.6 cm, respectively). Its lowest height increment (9.2 cm) was observed in the unfertilized seedlings. No significant results were obtained on the height and diameter increments of piling-liitan and supa and on the diameter increments of banaba, bangkal, dao, kariskis, and sakat. Similarly, percentage survival of all the species tested was not affected by fertilizer treatments. On the average, bangkal, kariskis, and sakat exhibited high survival rates (90.4%, 88.95, and 83.7%, respectively), which were above 80% minimum survival rate set by DENR for forest plantations. Dao, on the other hand, had very low survival rate ranging from 20% to 66.7% or an average of 47.4%. The results implied that during the 1st year of plantation establishment, 40 g complete fertilizer/seedling applied 1 month after outplanting was sufficient to enhance the height of bangkal, kariskis, and sakat, while banaba and panglomboien required 60 g complete fertilizer/seedling. On the other hand, 1st year height growth of dao can be improved by applying 20 g urea, 20 g complete or 40 g organic fertilizer.