Growing Concerns 583: Solving mystery of tree death

When a big tree fails in ways noticeable to an untrained eye it's usually years into a problem. The tree's reserves may have carried it for a decade or more, masking the decline.

I don't question the results you received from your samples. Trees in decline from environmental stress frequently have no significant pests or diseases. Pests that are present may be secondary to the wasting, opportunists exploiting a weakened host.

An arborist will probably look at your beeches' growth rate for the past five to ten years, seeking signs of when the trouble started. In that discovery may be keys to a solution. As an example, if a tree began struggling in the year a new driveway was installed, providing extra water and fertilizer to the undamaged portion of the roots may speed its recovery.

Short report

Many big trees are stressed this year...

...from oaks and red maples so pale as to be golden, to silver maples thin enough to see through. Here's how to assess a tree's growth rate and determine when the trouble began.

Examine an upper branch or a horizontal limb that extends to the drip line.

Measure how far it grew this year:

- Find the terminal bud at the branch tip, enclosing 2005's shoot.

- Find the terminal bud scar that marks the start of growth this spring. On a beech and many other trees that form terminal buds, this bud scar is distinct and enduring. Look for closely spaced ridges that encircle the twig like a turtleneck.

- Measure back from the terminal bud to this spring's terminal bud scar.

Next, determine and record past years' growth. Measure between each terminal bud scar and the one that preceded it.

Record several branches' growth history. Calculate annual averages.

Look for coincidences between tree growth and changes in the environment.

Compare your tree's growth to its species average, as listed in a book such as Michael Dirr's "Manual of Woody Landscape Plants." Uppermost branches should meet the species average. Lower and inner limbs will grow more slowly.

A beech like those in today's question might have this history:

2004: 7.5 inches, respectable for a beech's lower limbs, although upper branches should grow 12 to 18 inches per year.

2003: 4.375 inches

2202: 3.25 inches

2001: 3.75 inches

2000: 2.375 inches

1999: 0.125 inches

1998: 0.0625 inches

1997: 0.1825 inches

1996: 3.125 inches

1995: 2.5 inches

1994: 0.1825 inches

1993: 4.625 inches

Considering its history, this tree is not in decline but recovering from something that occurred in the mid-1990's.

 

Green thumbs up

to planting spring bulbs deeper than you ever imagined they could be. Tulips and daffodils planted ten to twelve inches deep are safe from digging animals. They also emerge a bit late in spring, less likely to be harmed by spring frost.

 

Green thumbs down

to abandoning your annuals now. Those like salvia, petunia, snapdragon and geranium that can handle cool weather will shine into October if you keep deadheading, watering and fertilizing.

 

 Original publication 9/11/04