I am working on the south side, where so many Pinyon Pines died during the 11 year drought. I am building raised beds and dragging stones downhill. I am also looking at the masses of deadwood still to be used for hugelkultur and some of which will be added to raised bed 8.
This photograph shows an open area where Pinyon and Juniper died back, and one of the piles of deadwood stacked up by the prior owners. It is ~3 feet high.
One study during the 2000-2002 drought said Junipers had up to 25% mortality but Pinyon Pines had up to 95% mortality. In general, Junipers are more common on drier sites and Pinyon on wetter sites. Our long drought changed the percentages on my 5 acres to favor Junipers, but in seedlings, Pinyons outnumber Junipers.
As I build raised Hugelkultur beds to absorb and hold water for my plants, I am creating a microenvironment that favors soil bacteria and microbial decomposition. These piles of deadwood in full New Mexico sun are decomposing in a different manner that studies say is also effective.
The photo shows the progressively smaller bits of wood and the accumulation of deeper colored soil beneath.
As I dug some out, you can see the top layer is deeper and in this spot is about 2 inches deep.
New Mexico’s arid environment, combined with 75% of solar radiation hitting bare soil, kills microbial communities in the top layer of soil. The UV radiation also broke composes wood. Even though the scientist approved UV radiation as a decomposer, it doesn’t improve soil moisture and carrying capacity for plants in the same way.
This is the material I will add to hugelkultur raised bed 8. By burying it, the retention of moisture and with a light mulch to cut UV rays that kill microbes, I am changing my soil composition in basic ways. Ways that are more compatible with plants that have higher moisture needs and that require their soil biota for health.
As I finish adding raised beds, I will still need to bury more deadwood in the food forest. Today I buried a few shovel loads of wood chunks and compost near a young Pinyon Pine. One study of pinyon-juniper mortality during the drought showed that under drought stress, Pinyons shut down for months at a time and burn their stored carbon much like we would burn our own fat and protein when we have no food. Junipers have a completely different procedure and shut down for about a month and use fewer reserves. Both drop branches under stress creating litter like in the photo. The litter builds up and decomposes, enriching the soil and eventually holds moisture longer. Perhaps not the easiest life… toss me an arm and you can live.
Long periods of drought weaken Pinyon Pines to the point they are susceptible to predators like Pine Bark Beetles, which go into overdrive to take out the weakest, most poorly adapted trees. Those are the trees becoming hugelkultur beds in my garden. I want to save the Pinyons of course, but the truth is that those left are better adapted to a warming planet.
I come from soft lands where soil is built by soil biota and worms and is alive. I live in a land where decomposition is more often accomplished by sterilizing UV radiation. From the beginning I kept saying “this soil is dead!” I was responding intuitively to irradiated soil. I have a tip for the scientist who decided UV radiation is just as effective as soil biota… it is not. Here’s where I am supposed to put IMHO. I am just not humble enough to even pretend. It is what it is and I use what I have.