Our 5-acre property on the Olympic Peninsula is forested with mostly Douglas fir and a few cedars. We want a logger to remove some of these trees so we can plant fruit trees, berries, and vegetables using permaculture design. We'd like to use the slash (stumps and branches) in a way that benefits the soil, but since it's not deciduous wood, it may not be good for hugelkultur or wood chips. Would biochar be a better way of using conifer slash to improve soil fertility? If so, is there a way to burn the slash for biochar without the expense of having it chipped first? We've considered leaving the fir and cedar stumps in the ground and planting fruit trees around them, but we'd like to hear how others have fared after making similar choices.
I think you could use the coniferous wood 'waste' for any of these techniques. Maybe a little bit of all of them. Some nice hugels with remial wood chips and biochar mixed into the pile sounds like a pretty good combo to me. Your soil was probably already built up largely from the decomposed and burnt wood from those trees or their predecessors so I wouldn't think it would make things a whole lot worse than what you already have for soil.
I've constructed hugels from predominately red fir with a little white fir, pine and some alder mixed in along with charred logs from slash piles and the soil from the slash piles as well. They've worked out pretty well for me so far. I don't have much in the way of cedar where I'm at but if I did I'm sure some would find its way into the mix as well. I think the biggest thing is to try to use as much of a combination of materials in various states of decay as you can so that no one material will dominate to such as a degree that it causes major detriment to the system. Reminds me of an old saying from one of my ecology classes: "The solution to pollution is dilution".
Firstly, totally unfamiliar with your own situation, I must state my personal bias here: DO NOT CUT DOWN HEALTHY TREES
If there is absolutely not enough light first try compromising with them. Ceder can have its bottom bows removed and will let in a surprising amount of light. Doug fir, in my experience, crown out and top off and then don't provide really ANY shade except for things that are directly behind them as staring at the sun. Kinda like an obelisk or something. That said large Doug Fir stands are sometimes thinned great effect (When cleared all the OM runs off with the first good rainy season)
Ceder is decomposed vigorously by a number of white rotting brown fungi and makes for great mulch along borders, especially when there is high competition.
I'm keen to grow trees for harvest and I don't have any regrets about cutting down a tree to extract the relevant products but we're also planting a load of trees to ensure this can be done again in the future. Just cutting down trees for waste to make some space to establish some productives is deforestation. I don't see how this can fit within a permaculture design or approach.
When's the best time to plant a tree? About 20 years ago. When's the next best time? Today!
Common Weeds And Wild Edibles Of The World (HD video)