OK, I might received some slack from the green peace advocates and environmental conservationists when forest trees are chopped down and all but bare with me, its not as bad as it looks.
I mobilized two units of excavators for this work. Due to equipment breakdowns, driver absentees and other unforeseen issues the work took exactly one whole month which in fact it could be completed in 2 weeks max. I have no prior experience in this work and there was a lot of lessons learnt:
1. Visualize and do a walk-through of the access road, terracing and path arrangements first based on the terrain with the excavator drivers to prevent incorrect terrain forming.
2. Ensure that the inside of the terrace is lower than the terrace edge (sloping down inwards) so that rainwater will not wash down to the terrace edges and damage/cut the soil slope.
3. Dig and remove all the tree trunk bases including as much of the bigger roots as possible.
4. Ensure that each and all of the terraces are leveled horizontally.
5. The more you excavate the hill slopes to form the terrace the more inefficient land use you'll have afterwards (because you'd still only plant one seedling regardless of the width of the terrace.
Prior to land clearing, the population of the existing trees consist of matured rubber trees > 20 years old, some secondary jungle trees, approximately 6 bamboo clumps and under story woody creepers and jungle shrubs.
Rubber tree wood are sought after by sawmill and furniture makers in Malaysia and most land owners whom engaged in land clearing thus chopping down their inherited rubber trees would sell the rubber timber to the sawmill. A word of caution though, selling rubber timber to even license sawmill is actually illegal. This kind of transaction is often done discreetly outside the knowledge of the authorities.
Durian Planting Hole Marking
It is a good idea to tasked the excavators to dig planting holes while it is still at the land. Ideally the planting hole should be at least twice the diameter of the durian saplings polybeg and since the excatavor's bucket size is about 2.5 ft, this would mean that with a single soil scoop, the planting hole is more than twice the polybeg size. A generous planting hole size of at least 2 ft is good because the back-filled soil afterwards would be loose/aerated soil and I could put more compost in.
The excavator drivers need to be guided on where the planting holes should be dug and for this I've marked each hole with a stake tied with red plastic tape. Prior to marking, I've measured each hole distance at 10 meters apart with about 1 meter distance from the slope edge of the terraces.
When it rains, obviously the planting holes would lose its shape and become shallow due to soil erosion from the sides. When that happens, I would dig it up a bit again. These planting holes ideally be left exposed to sunlight and air for a week or more prior to planting. This is to get rid of soil pathogens and other soil borne diseases that may exist in the soil.