The seedlings at Circle J-Norris Ranch could have been dying for various reasons. But, according to our data, the seedlings with the most protection had the highest survival rate. This is probably due the fact that the large wild animals (and domesticated animals) could not trample or eat the seedlings. The range cattle seem to be the greatest hazard to the seedlings. The plastic shelters provide additional protection from rodents and insects. We think that the plastic sheltered seedlings might experience a higher relative humidity than the seedlings without the plastic shelters. This might have a positive influence on their rate of growth.

When we studied the Survival Rate By Location graph we noticed that Year 2 had the highest survival rate. This could be due to Locations G and H being located on a slope with a northerly aspect. The soil tends to stay moist for longer periods of time.

Also, we considered the impact of nonnative grasses on the seedlings. Nonnative grass species are pervasive in most blue oak woodlands. The distribution of nonnative grasses at Circle J-Norris Ranch is widespread, but their distribution has yet to be mapped. These grasses might impact the survival rates of blue oak seedlings to different degrees in the different locations.

C. O’Brien, ed.

M. McGinn, S. Ertl
June 6, 2007

The number of surviving seedlings in the Blue Oak Field Study are dwindling. This is probably because animals are chewing on the roots, the weather has been too harsh, or the trees do not receive enough nourishment to grow.

We found that the trees with the most protection have a higher survival rate.

There seems to be a larger number of new seedling sprouting this year.