Tuesday, April 21, 2015

Climate change

Our trees are finally leafing out and we can assess how they weathered the winter.

It was a hard year for the apples. Last spring we planted a dozen apple trees and set up a drip irrigation system. Late June, a hailstorm stripped leaves and bark from the new trees and old trees alike. When Dave  checked them this spring, half of our old, well established trees had many, many dead branches and obvious signs of rot where the bark had been stripped from the trunks by the hail. Dave pruned them heavily and burned the branches. Three quarters of the new stock had no leaf buds and the branches snapped when we bent them, obviously dead. Dave ordered new stock. It will be  half a dozen years before we can expect a good harvest our own apples again, if the micro-climate around our trees hasn't changed too much.

It was a very dry winter, hardly any snow. We tapped our maples early because the weather had been so warm this spring and we didn't want to lose any sap. But it didn't matter. Out of 170 taps we only ended up with 40 quarts of syrup. We should have had close to 170 quarts. The weather didn't follow historic patterns of warm days and cold nights during March and April. We'd have a week of cold when the thermometer didn't top 32 and then a week of warm when the temperature didn't drop below freezing. About six trees produced sap during those days. Even on the few days when the temperature dropped below freezing at night and rose above 32 degrees during the day, a perfect day for the sap to run, our biggest sap collection was 35 gallons, far short of the 100 gallons we expected on a good day.  Was the ground still frozen down deep? Did we pull our taps before the sap really began to run? Were the trees drought stressed? Maples can only tolerate about ten days above 90 degrees in a summer. Did we have too many summer days when the thermometers topped 90 degrees? We don't know. All we can do is hope that next year will be more normal and that the climate has not  changed so much that the maples are dying.

When we first moved to the farm, we planted almost 100 walnuts to grow a college fund for our grandchildren. We planted trees in low spots and high spot,s on the south sides of hills and the north. We used stock from the DNR as well as sprouts from local trees. The trees have done well, producing an ever increasing crop of walnuts. They are growing in circumference and will probably be ready to harvest for lumber in 12 years when Kieran, our oldest grandson, is ready for college, if the climate cooperates. We have had very high ground water levels over the last half a dozen years. Last summer the township ran a culvert under our road to drain the pond across the road into our east fields. We have a small slough in that corner of the property, so the extra water was absorbed by the slough, but the row of walnuts closest to the slough have already succumbed to the high ground water levels. Hopefully, the trees planted on higher ground will keep growing, building our college fund.

The University of Minnesota just published a study on the importance of diversity for successful grasslands. Three years ago they published similar findings for forests, prairies and crops.We began diversifying our hay fields last year, adding red fescue, a grass, to our alfalfa mix.  Several of our pastures need replanting, we'll sow a  variety of grasses and clovers. Diversity in our tree crops seems to be the next direction we should go. We will plant more varieties of apples and in more diverse locations.

As the world warms, weather is predicted to be less predictable. Farmers will need to take this unpredictability into account. People working in the field of sustainable agriculture are already diversifying their farms. They recommend raising animals and grains, using their land for pasture and hay fields as well as other crops. Their farms are beginning to look like Old MacDonald's. With diversified farming, perhaps we can spread the risk of crop failure across many crops and phase out the dependence of most big  farmers on publicly funded crop insurance. Right now, diversification looks to be the best defense against the unpredictability of climate change.