Farm Focus: Warren Pears - Striking a Balance
In the heat of summer with wagons full of peaches coming in from the orchard, it's hard to believe we are already thinking about our Warren Pear harvest, but we are. We are thankful that the harvest for 2018 is looking very good! In 2016 we had a record low harvest of our Warrens and we were more than nervous. The Warren Pear is our signature fall fruit and important to our financial health.
After 10 years of healthy trees with vigorous production, our Warren trees started to decline significantly, both in health and yield. Yellow leaves, early leaf fall, and extremely low yields left us wondering what the problem was. The trees were too young for that level of decline, especially so rapidly. We think we've discovered that the decline we saw was due to the way the trees were grafted.
When nurseries propagate trees they use a rootstock (underground portion of the tree) which possess the desired soil interaction and disease resistance characteristics needed for the crop to be grown. Nurseries then graft on scion wood, a thin shoot that carries the genetics of the fruit you want to grow. Our Warren trees have a third component, called the interstem. This is wood grafted between the rootstock and the scion wood. Farmer Al believes that the interstem used by the nursery is causing the decline due to incompatibility with the Warren pear cultivar.
The interaction between the interstem and scion wood is stimulating the scion wood to overproduce fruit buds. We see this during bloom when the trees exhibit an extremely floriferous display of blossoms that are destined to become fruit. Though beautiful, all of those blooms represent energy the tree needs to manufacture to fruit.
The nursery used the inerstem intentionally in order to allow the trees to produce sooner in their lifespan and to have increased vigor and production. When the trees were young, they were able to keep up with the energy demands of the abundant blooms. We were happy with 10 boom years of bountiful harvests from our young trees. Now that the trees are mature, they are not able to produce enough energy to keep up with the bloom, thus the decline in health and harvest. Following one year of bust (low harvest and decline in tree health) we are employing intensive management techniques to moderate the negative effect of the interstem/scion interaction.
First, we are thinning out about 50% of the buds on the branches during the winter months so when spring comes we see less bloom. Currently, our crew is thinning small fruits off the tree, reducing energy requirements on the tree and allowing the fruit that remains to grow into delicious fruit. Both of these techniques reduce stress on the tree and conserve energy. We've also intensified our soil fertility program on the Warrens, as well as providing them with additional irrigation. Reducing the stress and increasing the trees' resources has paid off! We had a record crop of Warrens last year and this year's harvest is also huge. It seems we've been able to strike a balance between vigorous growth and intensive management.
Though we are currently delighting in the juicy sweetness of stone fruit, we are able to enjoy it much more knowing we will have plenty of buttery rich pears to enjoy come fall.