Bill Bruce on Forest Patrol

by Henry Harley Arnold

“I am not so sure about that,” commented Cecil. “According to the best advices which we have, the Indians in some instances used to burn out the woods so that they would not be bothered by the underbrush when they were hunting. Once they started a fire, they never tried to put it out. It always burned until it reached a natural barrier and then burned itself out. However, ordinarily the Indians were very much afraid of a forest fire, as it destroyed their villages. So it seems that they liked to have the fires under certain conditions, but they wanted to apply the torch themselves.”

“There must have been some mighty bad fires in those days,” said Bob.

“The lightning has always been responsible for many bad fires as far back as we have any records,” said Cecil. “Then, again, the early pioneers were not as careful as they might have been. There is one case on record where a young fellow was returning home after calling on a young lady who lived several miles away on another clearing. It was almost dark when he started home. He was either afraid to go home in the dark or was uncertain as to the proper trail to take. In any event, he set a match to a long burr of a sugar pine. That made a very good torch and served its purpose exceptionally well. However, when the first one burned so low that it was about to scorch his fingers, he lighted another one and threw the partly consumed one down alongside the trail. He continued this all the way home, and as a result there were many small fires, about equally spaced, burning through the forest.

“That young fellow was quite proud of his achievement. He had found a new means of illuminating the trail at night, but the early settlers were not so pleased with his accomplishment. There were not many of these pioneers in the locality and they had a mighty hard time in putting out those fires. The pine needles along the trail burned fast and furious for quite a while.”

“How can you tell the age of a tree?” asked Bill.

“That can’t be done until the tree is cut down,” said Cecil. “Each year during the life of a tree a complete coating of fibre is formed around the trunk of a tree underneath the bark. These coatings take the form of rings and are called ‘Annual Rings.’ They are formed in regular sequence around the center. By counting the rings the age of the tree is determined.”

“Why go to all that trouble?” asked Bob. “If there is one ring for each year and the rings are all the same size, why not measure the diameter of the tree and divide by the distance between the rings?”

“It would be much simpler if we could do it that way, but unfortunately the distance is not the same in any two different kinds of trees, or even in the same tree,” replied Cecil. “There are many things that affect the growth of trees. For instance, if a young tree is crowded for light and room, the rings will be very close together. Then if the surrounding trees dies or are cut down and the crowded condition relieved, the young tree will grow much faster and the distance between two rings may be the same as that between seven or eight rings during the period of slow growth. Two trees growing side by side, although they may be of the same species, may have entirely differently spaced annual rings.”

“How large do trees get?” asked Bill.

“That depends upon the species,” replied Cecil. “One of the giant trees in the Sequoia National Park was undermined by a creek a short time ago and fell. That, as you know, was a Redwood. They made a cross section of that tree seventy feet above the base and it measured eleven feet in diameter. The tree was 280 feet tall and had a base diameter of twenty-one feet. The annual rings showed it to be 1,932 years old. Of course those trees are the oldest living things in the world.