Hugelkultur using whole tree?

After this big storm came through we had a tree entirely downed. Perfect material for a hugelkultur bed. I'm wondering, though, if anyone knows whether we can just make a bed with the entire tree or is it more effective (quicker decomposition?) to cut it into smaller pieces. Any ideal size for the wood?

Easiest size to move around.

What type of tree was it? If a pine, then you will want to let is age a bit so the alleopathic nature of the wood will breakdown thereby not negatively affecting your plantings. Ultimately you want to have a level of breakdown in the tree to maximize the saturation of water during a rain / water spell. Smaller pieces would maximize breakdown rate and prove easier to handle. good luck