Every year, in the late spring and early summer months when nature is unfurling and beginning anew, from the Rocky Mountains to the Atlantic Ocean, and from southern Illinois to Canada, the air used to be abuzz with emergent eastern migratory monarch butterflies.
They’re still there, of course, but in far lower numbers than a century ago. This tragedy is thanks to a combination of agricultural pesticides, the eradication of milkweed by American farmers, and general habitat destruction throughout the three nations of North America.
From Three to five generations are born each year, with the first few generations only living for a few weeks.
But the last generation, born in late summer to early fall, is different: they have a life span of about 9 months and undertake an epic journey, traveling up to 3000 miles south in an annual migration that carries them to the welcoming montane oyamel fir and native pine forests of the state of Michoacan in central Mexico.
Believed to hold the spirits of the departed, their arrival coincides with La Dia de los Muertos, the holiday celebrated in Mexico that honors—and reconnects people with—those who have died.
Hundreds of thousands of tourists visit the spectacle at the Monarch Butterfly Biosphere Reserve annually, making the butterflies a significant economic factor. I (Storm Cunningham) have been one of them, and recommend this incredible experience highly. A UNESCO World Heritage Site containing most of the eastern population of the monarch butterfly, this area welcomes millions of butterflies from October-March.
Oyamel firs and native pines are uniquely suited to provide the climate and shelter that eastern migratory monarchs need to rest after their long migration — and to survive the winter. In fact, the size of the eastern migratory population is measured by the number of hectares of oyamel fir and native pine forest that they occupy. Here, they rest and conserve their energy until environmental changes trigger a new migration back north to lay eggs and start the cycle anew.
Far more than a beautiful, ephemeral harbinger of sunnier days and warmer temperatures, monarchs are prolific pollinators and critical to the health of our planet. While feeding on the nectar that comprises their diet, they pollinate many types of wildflowers — providing an invaluable ecological service to forests and farmlands across their range. They also provide an important food source for birds, small animals and other insects.
Unfortunately, monarch populations have been dwindling due to loss of milkweed and nectar plants, deforestation and degradation of their overwintering grounds in California and Mexico, pesticide use, and climate change impacts like out-of-season storms, severe temperature drops and heavy rainfall. All of these factors have combined to create a sharp decline, particularly in the past 20 years.
How Reforestation Can Help Monarch Butterflies
As mentioned, the Abies religiosa (Oyamel) tree, which has a lifespan of up to 300 years, helps form the traditional nesting site of the monarch butterfly. These unique trees are being lost due to a one-two punch of overharvesting and climate change. Their strong wood is used to build train tracks — and during the establishment of the Mexican railroad system, logging and manufacturing sites were established, with profound effects.
In addition to overharvesting impacts, the Abies religiosa can’t tolerate temperatures above 25 degrees Celsius (77 degrees Fahrenheit), and with steadily rising temperatures in its home range, it has been forced to retreat further and further up the mountainside in search of cooler conditions — at a rate of 10 meters per year.
By planting oyamel and other native tree species to restore montane oyamel fir and pine forests, we help protect vital monarch nesting grounds, restore degraded lands, improve water filtration and watershed health, protect vital ecosystem services for nearby communities, and more.
This year, the non-profit organization One Tree Planted is planting trees for monarch butterflies via two projects in and around the Monarch Butterfly Biosphere Reserve.
Senguio And Ocampo, Michoacán
One Tree Planted is planting 500,000 trees to restore 459 hectares of land in and around the Monarch Butterfly Biosphere Reserve in the municipalities of Senguio and Ocampo. The native tree species they’re planting are Oyamel pine, Pinus pseudostrobus (smooth-bark Mexican pine), Pinus leiophylla (Chihuahua pine), and Cupressus lindleyi (a cypress tree, commonly known as “white cedar.”).
This project focuses on two types of restoration: converting deforested farmland back to native forest, and forest restoration of areas that were clearcut for timber or lost in forest fires. By working together with local landowners, they’re able to restore vital monarch habitat, much of which is mountainous and not suitable for commercial or large-scale farming.
As the trees grow and the land around the Monarch Reserve is restored, pressure on the remaining forest habitat will be reduced, and vital resting places will be restored. In addition to benefiting the monarchs, the trees will protect forest microclimates, prevent regional desertification, protect wildlife habitat, sequester carbon, reduce erosion and the likelihood of landslides, restore natural springs, improve air quality, and more.
their planting partner works together with local and indigenous community leaders to ensure community support and the long-term success of the project. Communities and landowners are also engaged with educational opportunities to learn about sustainable forestry practices, including proper planting techniques, sustainable harvesting, recycling and waste management, and land and plant protection. As the trees mature, they’ll also improve livelihoods by providing a source of sustainable income.
Cerro Del Cacique, Zitacuaro, Michoacán
To the south in Cerro Del Cacique, Zitacuaro, Michoacán, One Tree Planted is planting 400,000 Oyamel and smooth-bark Mexican Pine trees to restore 400 hectares of land as a continuation of their 30,000 tree project there last year.
This land, which belongs to a variety of local, indigenous communities including San Juan Zitacuaro, Nicolás Romero, and El Aguacate, is part of the Monarch Butterfly Biosphere Reserve.
As One Tree Planted’s Latin America and Caribbean Project Manager Malcolm Porteus Gonzalez put it, “The success of this project opened many doors to the possibility of recreating reforestation efforts at larger scales across the Monarch Butterfly Biosphere Reserve and is the first step for conservation efforts in the Michoacán area for years to come.”
In addition to helping the butterflies, the planted trees will benefit the local community by improving their water supply, which comes mostly from natural springs and relies on healthy vegetative cover. The project will also help safeguard the local eco-tourism industry, which depends on monarch migration. Visitors travel from all over the country and world to see this incredible natural phenomenon.
Beyond their delicate, ephemeral beauty and awe-inspiring migrations, Monarch butterflies are one of nature’s most important pollinators. Today, they’re increasingly under threat due to factors ranging from deforestation to pesticide use and climate change impacts. Losing them would not just be a singular loss of a beautiful species, but would have a ripple effect touching every one of us through the food we eat and the health of the ecosystems we depend on.
Photo of Monarch Butterfly Biosphere Reserve is courtesy of World Wildlife Fund.