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How to tell the age of a tree


It is not always necessary to cut down a tree in order to find out how old it is. Each twig and branch bears a record of years, written in the scars of bud scales and leaves. In old trees the reading of these records is often a task, but with young ones it becomes a delightful amusement. It has the fascination of detective work. After your first successes, you find yourself questioning e every tree you meet. Your friends get interested with you, as soon as they learn the key that unlocks the tree's secret.

With experience comes facility, and the undertaking of more difficult problems. The old apple tree by the roadside challenges you to make out the story of its eventful life. You can learn to read the record of last year's crop. You can tell exactly how many fruits a particular branch has ever borne, and even whether they reached maturity or were picked green.

The promise of next year's crop is revealed to you, though you cannot foretell whether the flowers will be frosted. The veteran recites to you its past successes and failures, declares the year it came into full bearing, the time of the big wind or the ice storm that broke so many large limbs, and you can even give a shrewd guess as to wether the tree has been a profitable investment or not. It is as if the owner kept an account with each individual tree and opened up to you his book of record for this one.

But come, let us try our skill. Young trees shout their ages at us almost before we have time to ask for them. Let us go down where young maples are starting a "sugar-bush," or where young beeches cover the floor of the woods. Here are a graded series of reading lessons for us. We will leave the cripples for a later time, and consider only those which have grown as nature intended them to. It is best to begin with kinds that are characterized by rapid growth - that have big buds and lusty stems.

They speak a language that is clear and plain. Perhaps the first thing you notice is a ring of scars. What does this mean? Each branch finishes its year by forming buds. Every spring it begins to grow by casting off the scales that protected these buds over winter. The scales leave a little group of scars to mark the place of their attachment.

Now, on the main trunk of any little tree, let us count back from the tip to the ground. The length between each two of these groups of scale scars represents the growth of a year. Now we have the clue. The oldest side branches are a year younger than the main stem. Every branch, great or small, is normally a year younger than the stem that bears it. Each tells its age by its groups of bud scars. The youngest wood is set with buds in winter, and in summer all the leaves are borne directly upon shoots that grew from these winter buds.

Very commonly there is a difference in the bark of various years' growth. The newest shoots are greener, smoother and more herbaceous in texture than the older ones. All buds on older wood are dormant. They should have grown into leafy shoots the season after they were formed. When we have determined the age of a certain little tree, we may strengthen our faith by a further test. You think that a certain part of the stem is four years old. Cut it off and see if you can count around the pith the rings of wood inside the bark. If there are four, your judgment is vindicated.

Let us challenge every little tree that we meet. Those that have had a hard life will give us some problems. They are so small, and yet so old. But remember the fixed principle. Bud scales mean winter. Each group of their scars on a stem marks the end of another year's growth.

When we have learned to read these records in little trees, we may look up and read the same story among the branches of the older trees. The twig that gets the most light and air is lustiest in growth, and its story is the easiest to read. The picture shows us a twig of Norway maple. Let us count its groups of bud scars. Three full years of growth they record on a base which is four years old.

It is now the spring of 2002. In April, 1999, a bud threw off its scales at A and grew to B, bearing three pairs of leaves and a terminal bud. In April, 2000, this bud opened, and grew from B to C, bearing three pairs of leaves and a terminal bud. In April, 2001, the bud at C started, bore a pair of leaves, then died by some accident, and the two buds in the angles of the leaves carried the growth forward to D, and formed each a pair of leaves and a bud, which is full of promise for 2002.

This maple twig's story is a tale of woe. It found it on a lower branch where it rarely got any sunlight. It has borne twenty leaves whose scars are plainly seen. Each leaf should have had a bud in its axil, and these buds should have grown when a year old into side shoots. All these possibilities have failed except in the special emergency case at the top. A single bud below C remains, but it has been dormant for a year, and is probably dead. All the others have died and fallen off. But the lusty end buds, have better light and more air. The growth would probably have been better from this time forth if I had left the twig on the tree.

The final test of age is made by a slanting cut through the wood of the different years. Each year of age reduces the size of the spongy pith and adds a thin belt of compact wood. why is it so thin? The leaves are the nurses of their own buds, and the feeders of the twig that bears them. Growing in shadow, they are small; they get but little food from the soil and the air they call make but little starch to send to needy, dependent parts. Hence, the short growth made by this twig each year, the weakness of its buds, its failure to increase in diameter.

All these are but outward signs of the poverty that for years has been the portion of this unhappy little twig. But all over the treetop we may find to contrast with the ill-favored twig lusty ones that tell a story of free and independent life, where sunshine and sap and good fresh air abound.