National Arbor Day was founded by J. Sterling Morton in 1872 and is celebrated on the last Friday in April. This year it falls on April 30th. The simple goal of this day is to inspire people to plant, nurture and celebrate trees. So whether you’ve been thinking about planting a fruit tree to feed the family, a shade tree to save on summer cooling, a flowering tree to attract pollinators, or some trees to hang the hammock on this is a good time to plant as well as nurture and celebrate all trees.
Trees are remarkable in how they grow and adapt to their environment. Some trees, like crape myrtle, sycamore, madrone and cherry have especially beautiful bark. This is the tree’s protection from the outside world. Continually renewed from within, it helps keep out moisture in rain and prevents the tree from losing moisture when the air is dry. It insulates against cold and heat and wards off insect enemies.
The inner bark, or phloem, is the pipeline through which food is passed to the rest of the tree, It lives for only a short time, then dies and turns to cork to become part of the protective outer bark.
The next layer in is the cambium cell layer which is the growing part of the trunk. It annually produces new bark and new wood in response to hormones that pass down through the phloem with food from the leaves. These hormones are called auxins and stimulate growth in the cells. They are produced by leaf buds at the ends of branches as they start growing in spring.
Inside the cambium layer is the sapwood or xylem which moves water from the roots to the leaves. Sapwood is new wood. As newer rings of sapwood are laid down, inner rings lose their vitality and turn to heartwood.
Finally, the central supporting pillar of the tree is called heartwood. Although dead, it will not decay or lose strength while the outer layers are intact. A composite of hollow, needlelike cellulose fibers bound together by a chemical glue called lignin, it is in many ways as strong as steel.
Leaves make food for the tree. Their shapes help them reduce wind resistance, shed rain that could decay the leaf if left standing and produce chlorophyll. The narrow needles of a Douglas fir, for instance, exposes as much as three acres of surface to the sun.
There is a tree to please everyone. Don’t have much space for a fruit tree? Consider a Garden Annie dwarf apricot, a dwarf Garden Prince almond, Compact Stella cherry, dwarf Red Sunset nectarine or a Garden Delicious apple.
Rather not have fruit to contend with? How about a flowering crabapple, cherry or plum? Want a deciduous shade tree that grows fast? Red maples with blazing fall color fit the bill.
Need to screen a neighbor quickly? Then plant a honey locust or catalpa. Another fast growing,deer resistant tree is the silk tree. It’s flat topped, spreading canopy make this a good patio tree and is especially beautiful when viewed from above, as from a deck or hilltop. If left unpruned it will become a multi-stemmed tree but with training can be grown as a single trunk 10-20 foot umbrella. Fluffy pink flowers like pincushions bloom in summer. Grow it in full sun to partial shade. With regular water it grows fast. They are attractive to birds, too.
Be kind to your trees. They are a valuable asset to your home and our environment.