Oak Tree Masting Year

We are always observing the activities of the flora and fauna in our yard (native CA ecosystem restoration area), and this past fall, we became quite concerned when we noticed that most of the native Oak trees on our property (which are normally evergreen), were dropping the majority of their leaves, over winter. Were they overly drought-distressed? Succumbing to a disease? We had no idea, but were worried.

Then, as I was reading the amazing book, “Hidden Life of Trees,” I stumbled upon Peter Wohlleben’s description of how nut-bearing trees such as oaks will (in unison) drop a very high proportion of the leaves in their crowns, to make room for the ridiculous number of flowers (and later, the acorns) which they plan to make in the following year, which they have decided (in unison) will be a masting year. Masting years are the years in which the oaks bear a bumper-crop of nuts. They do this only once every several, unpredictable number of years – so as to produce more food than the regular population of nut-predators can possibly consume in a year, thus increasing the likelihood of successful procreation. They risk death by starvation in order to do this, but once masting year is over, they work hard to replace all the leaves they had jettisoned for the masting season.

So, I wrote the question in my diary, last autumn: does the leaflessness of oaks portend a masting year, where we live? Now, in the first warm sunshine after a long, rainy winter, we have the answer…

A masting year, it is! Achoooo!

So now, I know, when the oak leaves drop from a healthy-looking, California Coast Live Oak tree:

  • It is a good omen;
  • Plan to spend time in the autumn, harvesting and processing acorns;
  • Recognize that Nature will provide well for your family in the coming year.


Nature’s Temples

“Nature’s Temples: The Complex World of Old-Growth Forests,” by Joan Maloof (with illustrations by Andrew Joslin), is a profoundly inspirational work of science writing that describes the structure and ecology of old-growth forests.

The book begins with an awe-inspiring overview of the history of forests on Earth, the earliest known from fossil-records dating from 383 million years ago! Maloof discusses the role of forests in removing carbon from the atmosphere, and the surprising discovery that the largest, oldest trees are far more effective at this task than a multitude of younger, smaller, fast-growing trees. She presents a convincing case for the preservation of old-growth forests, on the grounds that they are essential for the survival and well-being of all other life on Earth.

Maloof then goes on to make the reader fall in love with all the living beings found in old-growth forests, one short chapter at a time. She introduces us, first, to the trees themselves, then one at a time to the birds, amphibians, snails, insects, herb plants, mosses, fungi, lichens, worms and mammals that are resident in old-growth forests. And it is truly a book of wonders.

One of the things I had always wondered was how deer and elk could find sufficient food in an old-growth redwood forest, in which the browsable branch tips are hundreds of feet high. The answer: Although the herbaceous understory might be shaded out, a rain of lichen from the lofty canopy provides ample nitrogen-rich food for them. But what is a lichen? It is a magical symbiotic alliance between photosynthesizing algae and mineral-harvesting fungi! Mushroom salad. And I had no idea how amazingly diverse was the world population of lichens, especially within the remaining old-growth forests.

The most surprising thing I learned from this book was that the (mostly non-native) worms found in North American forests north of the ice-age moraines – areas that had once been covered in glacial ice – are in fact doing more harm than good to the forests in which they are found. In order to develop the rich biodiversity that enables a forest to thrive into grand old age, a thick layer of forest-floor duff must be allowed to accumulate. The moist, decaying duff at the surface of the forest floor supports diverse fungi, which in turn support diverse plant life, and allow for the germination of tree seeds, which might otherwise lie dormant. If too many worms begin churning under the duff, too quickly, that mechanism for growing diversity in the forest is disrupted, impeding the growth and healthy development of the forest! And I had always assumed that worms were good for the trees!

Live and learn.

In fact, there are so many new things to learn, in the pages of “Nature’s Temples,” that the book bears repeated readings. It is a definite must-have volume for the shelves of a Druid library.