And here's another sign from the Dalrymple Creek trail:
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| This one I had to clean up a bit to be able to see the mistletoe photo. |
Sign text: Tree Parasites. Mistletoe, Witches Broom. Weyerhaeuser. 14.
Weyerhaeuser is the wood products company that left this patch of forest uncut, and provided the signage and pamphlets. 14 probably refers to the section in the now lost pamphlets.
I looked for the mistletoe in the trees near the sign, but didn't find any, possibly because it is near the tops of the trees, too far away to see without aid. Or loggers boots.
But 'way up there, there were clusters of witches' broom.
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| Witches broom in the canopy. |
Mistletoe causes the tree to grow fat branches; there may be a few in this photo.
The sign is wrong: mistletoe is a parasite. Witches' broom is not. Mistletoe is a plant that grows on the tree, mostly underneath the bark, taking nutrients and water from the tree. The shoots that bud out of the branches produce the seeds and expel them away from the host tree.
Witches' broom is part of the tree itself, a response to stress, in this case the challenge of the mistletoe, but it could also originate with other stressors.
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| A view of Dalrymple Creek. Notice the tangles of witches' broom at upper right. |
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Un letrero en el bosque nos advierta de la presencia de parásitos de los árboles.
Dice el letrero: Parásitos de árboles. Muérdago. Escoba de brujas. Weyerhaeuser. 14.
Weyerhaeuser es la compañia maderera que nos dejó los anuncios y los folletos (que ya no existen). 14 sería el número de la sección en el folleto que explica el letrero.
El letrero se equivoca. Muérdago es un parásito; la escoba de brujas, no.
El muérdago es una planta que crece a base del árbol; la mayor parte de la planta se esconde bajo la corteza. Allí toma los elementos nutritivos y el agua que necesita directamente del árbol. Los brotes que salen al aire producen sus semillas y las lanzan fuera del ámbito del árbol invadido.
Busqué alrededor del letrero para ver si podría hallar el muérdago, pero no lo vi. Creo que estaba allá lejos, arriba en la fronda.
La llamada "escoba de bruja" no es un parásito, sino la respuesta del árbol a un estrés, en este caso, el muérdago, pero podría ser, en otros sitios, algún otro problema, sea hongos, insectos, y otros organismos.
En las fotos se puede ver el lío de ramas que constituye la escoba de brujas.
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