There are 3 options for removing your orchard to make way for the new. There are some positives for each and some cons for each, here we will try to line them out without making it too complicated.
Pile and Burn
This is exactly what it sounds like, throw them in a pile and light them off. Here are some pros and cons:
Most people have the equipment readily available to complete this project, usually just an excavator and or dozer.
Can be done in-house with the existing labor force.
Can be done at a very low out-of-pocket expense if the equipment is in-house
Results in a low amount of biomass re-entering the soil if that is not desired.
Can be an arduous task to get them to burn up cleanly
Requires handling the tree several times
A lot of smoke to make the neighbors happy
Typically a lot of roots to deal with afterward
If not piled cleanly there can be a lot of dirt and debris mixture left behind.
Can be a very long drawn-out process.
Full all-in costs are generally higher than expected due to hand labor.
Subject to approved burn times enforced by DEQ.
Very weather dependent if there is a desire to avoid working in the mud.
Overall a pile and burn operation is great if a person wants a very low initial investment and is willing to work on it over a long duration of time.
Pile and Grind
This process starts much like a Pile and Burn operation. All the trees are ripped from the ground. The trees are then consolidated into a windrow or pile. The consolidation process generally requires an excavator and or dozer to complete efficiently. After the consolidation process is done a horizontal grinder is brought in to chew up the trees into a specified size usually called hog fuel and put into a pile with a conveyor belt. After the grinding is done the particles are spread back out over the ground or hauled off. After this, the ground must generally be ripped and raked to extract the remainder of the roots.
All material that passes through the grinder is very specifically sized
The most efficient method is if it is desired for material to be completely removed from the site.
Generally requires handling and transporting the trees several times to consolidate and then spread back out.
Is difficult to evenly spread out the hog fuel after the grinding is done.
Repeated tracking over the ground to consolidate increases soil compaction.
Residual roots still need to be ripped and gathered
Cost is usually the highest of the 3 processes.
Equipment is very specialized and generally must be hired out with highly skilled operators
In short, this is the best option for those wanting to repurpose the material for another use like bedding, or if it must be loaded and hauled off-site.
Mulch and Rotovate
This process is different from both of the others in that it does not require relocation or consolidation of the material, in fact, the more consolidated the less efficient the operation. The first step is to send in a large high-HP mulcher, to be efficient this must be at least 500 hp or more. The first mulcher drives right into the standing tree and pushes it over while mulching the trunk and crown of the root ball. This happens tree after tree through the entire mulcher in a continual motion.
The next step is to bring in a highspeed, high hp mulcher that will quickly reduce the mulched tree into finer and finer particles while evenly distributing the material. This may be done over 1-4 passes depending on the biomass density and the particle target size.
After the particle size is reached that is desired a rotovator on a 500+ hp tractor is used to thoroughly grind the stumps and roots into small pieces conducive to farming. After the initial grind on the stumps, the rotovator makes a full coverage pass over the entire area. This final pass further breaks down the roots and stump particles, fully mixes the mulch into the soil, and buries any over-sized chunks deep into the soil.
No need to consolidate trees.
Adaptable to different specifications and circumstances.
Because traffic is not as concentrated work can be done in wetter conditions.
Little to no hand labor is required.
Soil is thoroughly cultivated when completed in most applications.
Organic material is thoroughly spread and mixed into the soil as part of the process
No smoke or excess vehicle traffic transporting material off-site.
An acre can be completely converted from orchard to farmable at up to 10 acres per day.
Increased organic matter content.
Not generally suitable if the desire is to haul material offsite or process for other use.
If trees have already been placed in piles it may not be the most efficient method, however, this can vary.
Can be dusty when dry.
Generally slightly more expensive than piling and burning.
Very specialized equipment is not available to most farmers.
Increased variability of particle size over Pile and Grind
This method is how we attack most orchards, It is a very effective combination of processes to deal with a crop removal project without the need to haul off or burn.