October 7, 2016
The early Fall can be an extraordinary time for finding fungus in Southern California, as I was thrilled to discover at the perimeter of two NHMLA sites.
Along the border of the Exposition Park Rose Garden, adjacent to NHMLA’s Nature Garden, is a grove of remarkably large Ficus and Eucalyptus trees. Recently, two of the six or so Eucalyptus trees were sporting young fruiting bodies and more mature “shelves” of Laetiporus gilbertsonii, a fungus known as the California Chicken of the Woods. This species is a wood decay fungus common to California oaks and eucalyptus trees especially when they are old or stressed from something like drought, which we are experiencing in Southern California. These golf-ball sized, candy corn-colored blobs were as weird as they were wonderful.
More mature “shelves” of Laetiporus gilbertsonii were found on Eucalyptus trunks near the ground and as high as about 20 feet.
Later that week, in the parking lot of NHMLA’s Invertebrate Paleontology facility in an industrial park in Carson, CA (where NHMLA’s largest fossil collection is housed), I noticed this phenomenal fungus along the lot’s once-landscaped edge. Both specimens are, I think, Ganoderma applanatum, also a wood decay fungus and a common species found around the world. Interestingly, their difference in appearance is due to the age of the fungus: young = brown/orange and white, more mature = woody brown. What is odd about these specimens is that they are not growing on a tree but from a cinder block wall near the ground.
Ganoderma applanatum is called the “artists’s conk” (conk = fruiting bodies of a fungus attached to a tree) because its white undersurface turns brown when drawn on and can be used as a “canvas” of sorts to create etchings. Specimens have been reported to live as long as 50 years and Ganoderma applanatum conks on trees in mountainous African rain forests have been observed (by none other than the late Diane Fossey) to be collected by and gnawed on by gorillas.
Many thanks to citizen scientist Gregory Han for confirming fungus identifications. For more information on fungus finding and other mushroom-related events, check out the Los Angeles Mycological Society.
July 9, 2015
by Carol Bornstein
Photo by Carol Bornstein
Squirrels and humans have something in common – both love nuts. If you skip the added salt and oil, these tasty “fruits” are good for you, too. And if you are interested in foraging – with permission and proper identification, of course - several of California’s native trees and shrubs offer up some mighty flavorful nuts. Just ask the squirrels!
For centuries, Native American tribes throughout California have harvested native hazelnuts, pine nuts, and walnuts. Birds, squirrels, and other wildlife also feast upon these nutritious foods. Here in the Los Angeles Basin, southern California black walnuts (Juglans californica) are still relatively easy to find in the Santa Monica Mountains, growing among coast live oak, toyon, elderberry, sycamore, and other woodland or chaparral vegetation. This deciduous tree is an important food source for Western gray squirrels (Sciurus griseus) and ground squirrels, and many kinds of birds use cavities in older trees as nesting sites. It is ironic that wild populations of this native tree, so widely used as rootstock for commercial walnut orchards, are threatened by urbanization. Recognizing this, the city of Los Angeles added southern California black walnut to its short list of protected tree species in 2006.
If you visit the museum’s Nature Gardens, you can see a thriving young tree just east of the bird-viewing platform (see map above for location, indicated by the yellow arrow). We planted it two years ago from a 15-gallon container and since then it has tripled in size (although at one point we almost lost it thanks to Eastern fox squirrels (Sciurus niger) chewing on the tender trunk).
Imagine my surprise when I noticed a crop of young walnuts on our tree this past spring. Six round, bright green nuts were beginning to ripen among the leafy branches. What fun! A couple weeks later, only three were left. Suspecting that the squirrels were helping themselves, we tied protective cloth bags around the remaining nuts so that visitors would have a chance to see mature walnuts on the tree. Well, somehow a squirrel managed to get two more nuts, further evidence that the Nature Gardens are indeed habitat for wildlife!
Even if the solo remaining walnut disappears, we are confident that the tree will produce another, bigger crop next year. It would be fun to use the husks for dye and to share the oil-rich nutmeats with some lucky visitors.
August 21, 2013
Trees don't have heartbeats. You can't put a stethoscope up to a tree trunk and expect to hear that familiar dull thumping that gently insists, "I am alive." At least I'm pretty sure you can't, no matter what hardcore LOTR fans say, Ents do not exist! However, this doesn't mean you shouldn't try putting a stethoscope up to a tree and listening.
What do you think you would hear?
Alex Metcalf knows.
Okay, so I know that silver trumpety thing isn't a stethoscope, but it would be really gross for a Museum to let thousands of school children and other visitors use the same stethoscope to listen to a tree. Since we're so considerate of our visitors and we really wanted everyone to be able to listen to the inner workings of a tree, we worked with British artist, Alex Metcalf. He created a listening tree installation in our new Nature Gardens by hooking up microphones to one of our coast live oaks, Quercus agrifolia.
When you put your ear up to one of the four trumpets Alex installed, you'll hear one of two things. First, there's a deep rumbling sound that is the amplified sound of the oak vibrating. If you're lucky enough, especially if you are visiting on a warm day, you'll likely also hear some tiny popping that is the sound of "water passing through the cells of the Xylem tubes and cavitating as it mixes with air on its way upwards."
Xyle-what you say? You see, trees have a system a bit like our veins that moves water, dissolved nutrients, and food between the leaves, trunk, and roots. Botanists call it a vascular system and it consists of two main cell types, xylem (ZI-lem) and phloem (FLO-em). Xylem tubes are the main way trees and other vascular plants get water from roots to leaves and other parts. Alex explains, "as the leaves lose the water through evaporation the cells below the leaf become drier and they in turn pull water from the next cells below, this carries on down the tree all the way down to the roots. The water molecules cling together and form a water chain from the leaves to the roots under tension-cohesion."
He continues, "The Tree Listening Project aims to provide an experience that links both science and art by engaging the public with what happens inside a tree, and to excite and inspire a keen interest in trees."
Hopefully this has inspired a keen interest in visiting our Nature Gardens to listen for yourself. So go grab your bike, jump on a bus or the train, or put the pedal to the metal in your car and come on down to the Nature Gardens and hear our oak tree telling you, "I am alive!"
February 2, 2012
The North Campus is the proud parent of some baby oak trees!
Baby coast live oak sheltered by wallCarol Bornstein, our new Director of the North Campus Gardens, discovered a couple of oak saplings on one of her recent outdoor forays. The babies are coast live oaks, Quercus agrifolia, of which we recently planted several trees. We've also planted another species of oak, the Engelmann oak, Quercus engelmanni (we planted only three of this species). Both species reside in the section of the garden called the urban wilderness which is composed of several kinds of California native trees and shrubs.
This might be the mother oak!Oak trees provide amazing habitat value, and this is the main reason we planted them. By putting in such a sizable stand of oaks we're hoping our created wilderness will provide habitat for a whole slough of organisms rarely, if ever, seen before in Exposition Park. In just one oak tree it would be easy to find hundreds of species of associated plants and animals and thousands of individuals (think how many birds, ants, or squirrels you find in an oak tree). One species that has already shown up with our oaks, is a tiny insect called a whitefly.
Crown whitefly nymphs on oak leaf(each nymph is only 1 millimeter long)It was once again thanks to Carol, who was out inspecting our lovely oaks, that we discovered these small insects. At first we thought they might be a scale insect, but Brian Brown, the Museum's Curator of Entomology, identified them as crown whiteflies, Aleuroplatus coronata. As adults these small white homopterous insects (group of insects consisting of aphids, cicadas, scales, etc) fly around to find a suitable location to lay their eggs. For the crown whiteflies their plant of choice is oak. What you see in the image above are the nymphs (immature forms) of the whitefly, they have no wings but are covered with white waxy secretions that make them look like little crowns. The nymphs feed on the leaf's juices by piercing and inserting their mouthparts into the leaf. They can cause damage to the plant's health if their numbers are high enough, and they can also transmit disease organisms from one tree to another (not unlike mosquitos transmit malaria).Go check out your local oaks and see what animals live on them!
July 29, 2011
Have you ever seen a wild parrot in L.A.? Like many other North American cities, Los Angeles has a healthy population of many species of parrots, the most commonly seen of these species in Exposition Park is the Yellow-chevroned Parakeet, Brotogeris chirri.
Yellow-chevroned Parakeets feeding on coral tree nectarJail Break!People like to keep parrots as pets. To satisfy this demand, literally hundreds of thousands of parrots have been imported legally (and untold numbers illegally) into the United States over the past 50 plus years. In some cases this demand has lead to demonstrable drains on natural populations and even endangerment of some species. Inevitably, imported birds escape or are released, and over the decades enough free-flying parrots have survived to establish breeding populations in the U.S.A., particularly in metropolitan areas of south Florida and Southern California.Time to Get Liquored UpIf you’ve never seen a feral parrot around L.A. you might start looking for them in trees. At this time of year the parrots can be seen feeding on blossoms and nectar in flowering coral trees in the genus Erythrina (see picture above). This behavior is not unique to feral parrots as coral trees also appear in their native range. However other food sources they exploit in this region, such as Eucalyptus, are not found in their native range which is another example of adaptation to our altered L.A. landscape.Yellow-chevroned Parakeets are native to Brazil and adjacent areas, and were introduced to L.A. earlier this century. No one knows exactly how the introduction happened, but we do know it was from parrots that were imported here for the pet trade.
April 29, 2011
A pair of Bushtits, Psaltriparus minimus, just built their nest in the live oak tree behind the Butterfly Pavilion. Kimball Garrett, our resident bird expert, found the nest this Monday and promptly sent me an e-mail detailing the nest's location. As soon as I got into work on Tuesday morning, I headed out to the Butterfly Pavilion to check it out.
Adult Bushtit, Psaltriparus minimus
Thankfully Kimball had given clear instructions to find the nest, as it was very well hidden in the oak foliage. The effort was well worth it, as it was one of the coolest nests I've ever seen in the wild. As the picture below shows their nests are woven from dry plant material and hang from branches of the tree. They are small and dainty, this one measures about seven inches from top to bottom. The small opening at the top of the nest, which is only about an inch in diameter, is just big enough for the adults to enter and exit.
Bushtit entering nest
After spending a good portion of my morning watching the nest, I realized I had to blog about it. But what is a blog without images, or even better some actual video footage. I ran up to my colleague, Sam Easterson's office to see if he could get some for me. Sam recorded the nest for about an hour, and we captured some interesting behaviors, including removal of fecal sacs! A fecal sac is clean, tough membrane that encloses the excrement of young birds. Not all birds produce fecal sacs, but for those that do sacs are usually produced directly after each feeding and promplty removed by the adult to maintain a clean nest interior.
Bushtit cleaning nest
Sam Easterson is a video naturalist and also our new Media Producer for the North Campus and Nature Lab exhibits. He's really into implanting cameras into natural environments, and is best known for his animal borne imaging work.
March 16, 2011
This week we have been planting trees in the Transition Garden.
Before I launch into an animated discussion on the individual plants we've chosen for the space, let me give you a basic primer on what the Transition Garden is all about. Firstly, this is the space that ramps you up from the lower level of our new Car Park to the Entrance Plaza where you'll get your tickets. It is a nice gentle slope, so it will be easy for people of all abilities to make their way into the North Campus. It is also a stepped garden on a fairly severe slope. With these points in mind Mia Lehrer + Associates (ML+A) had to design a garden that would function physically, biologically, and thematically (we wanted more than just a random selection of plants). Thanks to ML+A this garden tells a great story.
The Story of Plant Introductions in Los Angeles
The plants that exist in L.A. today are a mixed and varied bunch, a real representation of our altered nature. They have been brought here purposefully and sometimes accidentally. As one enters the ramp from the lower deck of the Car Park you'll encounter plants introduced to L.A. over the last 200 years. So far we have California Pepper Trees, Schinus molle, from Peru; iconic Los Angeles palms, Washingtonia robusta, from northwestern Mexico; Olive trees, Olea europaea, from the Mediterranean basin; Citrus species from Asia including Eureka lemon and oranges; and finally Red Ironbark Eucalyptus, Eucalyptus sideroxylon, from Down Under. Check out this picture to see the progress!
Photo by Cordell Corporation