Ranger Steve’s Nature Niche–Spruce branch tips

Pounding front feet, a flicking tail, and loud chatter from a red squirrel demonstrates its defiance as it scolds me in his woods. I do not view the woods as his, mine, or yours. We live and share a space for a short time on Earth and hopefully leave it healthy for those that follow us. We all impact those around us and red squirrels bring benefit and harm to spruces. Gray and Fox Squirrels seem more tolerant of my presence. All three species give me space but the red squirrel is feistier.

Gray squirrels are most comfortable in extensive an unbroken forest dominated by oaks. Fox Squirrels prefer a deciduous forest with openings. The red squirrels claim dominance in the coniferous forest where they let intruders know they are trespassing.

At the Howard Christensen Nature Center a plantation of Norway spruce referred to as the Enchanted Forest is home to red squirrels. In the forest’s youthful days, green boughs were in contact with the ground and there was more open space among the trees. Younger aspen trees grew in the surrounding area. As the spruce plantation grew, more shade was cast upon the ground. When I first arrived in 1979, the trees were tall and sunlight reached the ground in few locations. Those locations bore luminescent bright green moss. Though it was reflected light, one would think the light was shining directly from within the moss – hence the name “Enchanted Forest”.

In winter the forest is quiet unless one passes too close to a red squirrel. Often we do not see or hear the squirrel but other evidence of its presence is abundant. It took some time for me to link the evidence to the red squirrel. Six inch green spruce branch tips regularly cover the ground in winter. I wondered why. It does not seem that they would break free from the tree in mass. A strong windstorm or ice covering should not cause branch tips to break.

Finally I realized red squirrels venture toward branch tips to eat lateral buds along the branch. Buds swell most toward branch tips and their succulence is preferred. The bud at the branch tip would taste even better but the branch becomes too flimsy for easy access.

When the squirrel eats the two buds along the side, the remaining tip falls to the ground. If it does not fall immediately, wind will break the weak gnawed area causing it to fall in short order. On the ground the red squirrel could enjoy the terminal bud that it could not reach when it was in the tree. I do not find evidence that it eats those buds but I have not really inspected the new and growing green carpet that thickens under spruces as winter progresses. Mice or other ground animals might find good nutrition just laying around for their taking. It does not cross their minds to thank the squirrel for making food accessible. The squirrel’s action might even be compared to us putting out birdseed. Actions of one animal in nature niches often have positive effects for other animals.

One would think biting branch tips off would only cause harm. The squirrel activity also has some positive impacts for the tree. We prune Christmas trees to cause them to form shorter bushier thick growth. The squirrels do the same for Norway spruce. It encourages the tree to put more energy into vertical growth and helps prevent growing branches into a neighbor’s space. It forces the tree to spend energy for upward growth that keeps its head in sunlight. That helps the tree live instead of being shaded to death by neighboring trees.

Natural history questions or topic suggestions can be directed to Ranger Steve (Mueller) at odybrook@chartermi.net Ody Brook, 13010 Northland Dr, Cedar Springs, MI 49319-8433.