West Bench Trail on Grand Mesa sparks interest in pigments of leaves
The question one ponders while hiking or riding through a stunningly beautiful stand of aspen quaking in the breeze, flashing yellow and crimson red, is this: How the heck do they change colors like that?
Of course, that was the question of the week last week. This week, it’s more like, “How much snow did Grand Mesa get?”
Since I managed a hike along the West Bench Trail on Grand Mesa last week, prior to any snowstorm, here’s what you may have missed: Aspen quaking in the breeze, flashing yellow and crimson red; dark green spruce and pine decorated with fallen yellow leaves; a hiking trail thickly layered with those same fallen leaves; T-shirt temperatures, clean, fresh air, crystal blue skies with billowing thunderheads floating by.
I’m still thinking of last week’s question, though, and here’s the answer:
Tree and plant leaves contain pigments that give them their color. Three pigments are involved in fall color:
Chlorophyll — gives leaves their green color;
Carotenoids — provide the yellow, orange and brown colors;
Anthocyanins — give the red and purple colors. In contrast to the other two pigments, anthocyanins are produced in the autumn, in response to bright light and excess plant sugars in the leaf cells.
During the growing season, most tree leaves are green because they are full of chlorophyll. Plants use chlorophyll to capture sunlight for photosynthesis, the process that enables them to manufacture their own food.
The amount of chlorophyll is so high during the summer that the green color masks all other pigments present in the leaf. As the days grow shorter in the fall, chlorophyll production slows down and eventually stops. The carotenoids and anthocyanins that are present in the leaf then become visible.
Now that we’ve covered that topic, you should know that the mesa did, indeed, receive some snow this week. That doesn’t mean it’s snowed under and you should get your skis out. However, you might not be hiking in a T-shirt for the rest of the hiking season — at least if you travel to the mountain instead of the desert.
What’s more, even if the colors have faded, West Bench Trail is still a great hike, and it’s easy to find: Take Interstate 70 east into De Beque Canyon and Exit 49, the turnoff to Powderhorn/Grand Mesa. This is Colorado Highway 65, the mesa’s Historic and Scenic Byway.
Travel another 28 miles, through the town of Mesa, past Powderhorn Ski Area, and up a couple of switchbacks past the sledding hill at the old ski area. Keep going up the switchbacks above the sledding hill and after the road flattens out a bit, you’ll find a wide spot on the right side of the road at Jumbo Lake.
Jumbo Lake really isn’t. In fact, the lake is quite small, but it’s a great jumping-off place for both the West Bench Trail, which travels generally west, and Waterdog Trail, which is across the highway and heads north, then east.
Follow the West Bench Trail around the north end of the lake, behind the cement restroom facility. There’s a relatively new pedestrian bridge going over the spillway at Jumbo Lake. Walk over that pedestrian bridge and keep trekking until you hike down a slight incline heading toward the old rangers station below Jumbo and through the recently redesigned Jumbo Campground.
Eventually, you’ll find a sign pointing toward West Bench Trail to the left, but if you get confused here, find the next semi-new pedestrian bridge going over Sunset Lake, the next lake below Jumbo. The trail used to cut to the right and across the creek below the Ranger’s Station.
The local beaver population, however, rendered that old narrow, wooden structure inoperable a couple of years ago. That’s when the Forest Service installed the new pedestrian bridges.
Soon after crossing the second bridge, you’ll come into a section of private cabins that have been here at least as long as the old ranger station, which was built by the Civilian Conservation Corps in 1941.
You’ll want to take a right turn at the top of the next hill, and continue past the cabins. Soon you’ll be winding your way along a bench of the mesa that lies in the transition zone between aspen and dark timber. The trail meanders in and out of the shadows, in and out of the pine, in and out of the aspen, for the most part traveling in a westward direction.
This trail is very popular and offers a wide single-track ride for mountain bikers when there’s no snow on the ground. It’s also open to horseback, but closed to motorized vehicles year-round. The elevation never changes much and before you know it, you’ll be looking over the Powderhorn Ski Area, a magnificent view.