Saguaro National Park is split into two sections on the east and west sides of Tucson. We went to the east side today. Saw the video and information at the visitor center and then drove the eight mile scenic loop. It was a very beautiful and interesting visit. The Sonoran Desert of southern Arizona is the only place these plants grow, at elevations from sea level to 4000 feet.
Saguaro are amazing plants. They are massive at maturity…..normally 40 to 60 feet tall. When fully hydrated the biggest can weigh from 3200 to 4800 lbs. Their size is something I never really got the idea of from pictures. The largest one ever measured was 78 feet tall. They live 150 to 200 years. They are very slow growing……a ten year old plant might be only 1.5 inches high. They don't start flowering until they're 6 feet tall which could take 35 to 70 years. They don’t start producing arms until they’re 15 or 16 feet and 95 to 100 years old, although some never grow arms. They are a big part of the ecology of the Sonoran desert, providing food to all who feed on their flowers and fruit (birds, bats and insects) and homes to all sorts of birds and other critters. Woodpeckers make holes for nests, then when abandoned other birds take over the holes to use as homes. The spongy water-holding interior keeps the nest holes cool in summer and warm in winter. A very useful condo.
Saguaro bird condo
Saguaro forest
It’s easier to get an idea of their size by seeing one next to the visitor center. It has to be close to 150 years old and is about twice the height of the building. Transplanting saguaros can be done successfully but the bigger they are the more difficult it becomes. I’m guessing the very large saguaros around the visitor enter were there originally and the building was placed near them. Their root system is a combination of a 2 to 5 foot tap root plus a maze of shallow roots going out about as far as the plant is tall. They grow so very slowly you can’t plant a 2 foot specimen and hope to live long enough to see it reach flowering height.
Saguaro babies need to be protected from the brutal summer sun so often are found growing under mesquite trees......thus the "mesquite nursery tree" label on the picture below. They produce about 2000 seeds per individual fruit, so when you look at a panorama of the saguaro forest it's obvious that not a lot of them reach the age when they can reproduce.
The destruction caused by ranching, mainly with cattle trampling young saguaro, nearly destroyed the saguaro forest. The national monument was set up in 1933 to protect the area and it is now a designated wilderness. There were two big die-offs of saguaro years after the wilderness area was set up which had nothing to do with cattle. It was then discovered that below freezing temperatures for more than 20 hours would kill them. That's something no one can do anything about.
They thrive in areas that don't get enough rain to saturate the soil which makes them unstable. They are incredibly efficient at taking in and storing water so can go for a very long time without rain. There are crested saguaros which have a beautiful crest of knobs across the top. They are rare, possibly because they make the cacti more vulnerable to being blown over. And it can definitely be windy......it was blowing pretty hard by the time we left in late afternoon. Among all the saguaros we saw today we couldn’t find a single crested one.
When they die and all the flesh is gone, their woody skeletons are left standing until gravity takes them down. Even then they provide homes and food to critters, mostly insects by that time. A lot like the remains of trees in a forest.
Finally, not a saguaro! This is a teddy bear cholla. It has masses of straw-colored spines and has a beautiful golden glow about it. It has a long trunk with this mass of short spiny arms on top which, at a distance, gives the impression of being soft and cuddly like a teddy bear. It actually looks more like Medusa’s hair with cactus arms instead of snakes. It’s also called jumping cholla because the segments detach so easily they appear to jump onto whatever has brushed by them. This is the cholla’s method of propagation since its fruits are usually sterile. I’ve read the spines can be very difficult to remove from your skin if you touch one. I always want to touch stuff but I’ve read enough about cactus spines to know not to do it. I’m glad I resisted the urge with this one because I didn’t know about the removal difficulty until later.
This has been your “more than you ever wanted to know about saguaros” installment!
No comments:
Post a Comment