Forest farming in northwest Washington supports resilient forest ecosystems
Estimated Reading Time | 10 minutes Management Goals | Diversifying income and adapting to climate challenges Audience | Farmers and land managers Project Area | Acme, Washington |
Neil McLeod is the owner and operator of Neil’s Bigleaf Maple Syrup, a 200-acre forest in Acme, Washington that produces maple syrup. Tapping bigleaf maple trees for sap in the context of a multispecies, diversified forest is a form of forest farming. The U.S. Department of Agriculture, Natural Resources Conservation Service defines forest farming as “managing or establishing stands of trees or shrubs in coordination with the management and/or cultivation of understory plants or nontimber forest products.” The overstory and understory layers in forest farming systems are not always distinct. In the case of Neil’s operation, he manages bigleaf maple trees (Acer macrophyllum), which make up one layer of vegetation, while other native trees form additional layers. Species such as western redcedar (Thuja plicata), grand fir (Abies grandis), and Pacific madrone (Arbutus menziesii) are encouraged to grow alongside bigleaf maple. When managed together intentionally, this diverse mix of species forms a multilayered cropping system that produces a harvestable product while maintaining the forest ecosystem.
Bigleaf maple is considered a commercial hardwood tree species, but it often has higher felling, yarding, and milling costs than other trees in Washington State. It also often yields a lower price compared to other tree species in Washington. Additionally, timber operations have long harvest intervals; decades can pass between harvests. Because of this, it can be difficult for forest landowners to generate a steady income from selling timber alone in bigleaf maple-dominated forests.
Bigleaf maple forest ecosystems also support many types of flora and fauna, including woodpeckers, bald eagles, elk, black-tailed deer, rough-skinned newt, tailed frog, western red-backed salamander, and a diverse array of fungi, mosses, and lichens. By engaging in forest farming and harvesting nontimber forest products like maple syrup, Neil generates a reliable income while supporting an ecosystem that is vital for many plants and animals.
Maple tapping in the Northwest
Tapping maple trees is common in the East and Midwest. Historically, it has not been common in the Northwest because the unpredictable freeze-thaw cycles lead to inconsistent sap production. Twelve years ago, Neil started experimenting. Before that, he had been a beekeeper for years until his hives unexpectedly died. Needing a sweetener for his morning coffee and without the ability to produce his own honey, Neil decided to try tapping a bigleaf maple on his land to see what would happen. He had low expectations at first. “Everyone told me, ‘It can’t be done on the West Coast’ and that it wasn’t worth the effort,” says Neil. Still, he kept experimenting. After several failed trials, he figured out the right tapping technique. “I got really good at it,” Neil says. “I could pick out the trees to go after, I hit the runs just right, and before long, we were making a lot of syrup.”
Managing a mixed-species landscape
Neil McLeod stewards multiple tree species in an integrated forest farming systems, including bigleaf maple, western redcedar, and other native Washington trees.
Neil cares deeply about protecting wildlife, so maintaining a diverse forest ecosystem is one of his top priorities. He manages his land so that roughly 80 percent of the trees are bigleaf maple, and the remaining 20 percent are other native trees like western redcedar and grand fir. By stewarding a mix of species, Neil is creating a more ecologically complex system than if he managed for only one species.
To keep his forest healthy, Neil removes diseased, dying, and dead trees every few years. This helps prevent the spread of disease and gives the remaining trees more space and sunlight to grow. With less competition, these trees become more resistant to potential pest outbreaks. Removing weak trees also reduces crowding, which allows Neil's bigleaf maple trees to produce higher yields of sap. However, Neil does not thin healthy trees.
"My philosophy is largely to leave the forest alone as much as possible," Neil explains. When Neil removes weak or dead trees, he always follows that task by planting new trees in their place. In addition to maples, he plants a mix of native trees to ensure that the forest remains diverse.
Sap collecting process
Harvest is facilitated by a network of spiles and polyethylene tubes that run through the forest and connect to a vacuum pump.
Sap harvest and processing are the most labor-intensive parts of Neil's operation. The sap harvest season lasts from late December to early February, when nights are still cold, but the days are getting warmer. To collect sap, Neil developed an elaborate harvest system throughout the forest consisting of spiles (small metal taps) inserted into trees to draw out the sap. The spiles are connected to a hanging network of 1-inch polyethylene tubes. These tubes, suspended from trees, run horizontally and are connected in a complex network throughout the forest that leads to a vacuum pump. The vacuum gently pulls the sap out of the trees, through the tubing, and into a collection tank, increasing the speed of harvest. Neil finds this vacuum-based harvest system to be much more efficient than the common gravity-fed system in which sap is gravity fed into tanks in different parts of the forest and transported to the main processing center by truck. Thanks to his vacuum harvester, Neil has been able to significantly reduce his labor and gas costs while maintaining a consistent flow.
Once the sap is collected, Neil refines it into syrup. First, he runs the sap through a reverse osmosis filter, which removes some of the water and increases the sugar content to 10 percent. Next, he boils the sap in a machine called an evaporator at 219.7 °F until enough water evaporates and the remaining liquid reaches the desired consistency. “When it gets to the temperature I want, the machine automatically opens a valve and pours off the syrup,” explains Neil. He stops the process once the syrup reaches a sugar content of around 68 percent, resulting in a thick and sweet final product.
Neil uses a vacuum pump to pull sap out of trees, which reduces labor costs.
Cleaning the network of taps and harvest pipes several times a year is another important management task. Previously, Neil cleaned them with bleach, but he stopped because he did not want the bleach residue to contaminate his product or the ecosystem. Today, Neil opts for a more natural cleaning solution by collecting excess sap and fermenting it into a low-acidity vinegar. In his experience, this vinegar cleans the pipes successfully without leaving behind contaminants. Because Neil produces vinegar as a cleaning solution from his own sap, he spends less money on external inputs.
Today, Neil’s property has around 600 taps, producing between 20,000 and 40,000 gallons of sap most years. After boiling, this results in roughly 200–400 gallons of syrup. He sells his syrup both online and to restaurants, and he notes that there is always more demand than supply.
Climate risks and adaptation strategies
Higher winter temperatures
By filtering and processing with specialized equipment, Neil is able to produce viscous, sweet syrup that maintains its quality despite Washington's winter temperature fluctuations.
Maple syrup production is sensitive to weather fluctuations. “Weather is always a challenge. Our winters are completely different from the East Coast's winters,” explains Neil. In many regions that produce maple syrup, nighttime temperatures stay below freezing during the spring, while daytime temperatures often rise above freezing. This creates a steady freeze-thaw cycle, leading to consistent production of high-quality, clear sap. In Washington, however, nighttime winter temperatures regularly fluctuate above and below freezing. This can cause pressure changes inside the tree that form air bubbles in sap. The result is that in some weeks, Neil’s land yields high-quality, clear sap, but in other weeks it yields low-quality, foamy sap. This trend is expected to continue—climate models project that Washington's winters will get warmer in the future. To deal with this challenge, Neil developed a specialized filtration system that separates foam from the sap. This equipment helps Neil quickly and efficiently manage the unpredictable sap quality caused by Washington’s oscillating winter temperatures.
Increased risk of flooding
Neil's land has a high water table, and the creek that runs through his property often rises during the winter, causing seasonal flooding. Because the ground stays wet for much of the year, logging in these areas is difficult, and building houses or traditional farming is not an option. “It’s kind of considered useless land,” says Neil. “It’s hard to log it, you can’t build houses on it, you can’t farm it. But it does produce an awful lot of sap.”
Flooding in Washington State is expected to become more frequent and severe in the coming years because of climate change. Instead of fighting these conditions, Neil decided to work with them. Since bigleaf maple naturally thrives in wet environments, he found a way to turn a challenge into an opportunity. "Some of the best runs I've ever seen are after major flooding," says Neil. Choosing to lean into these challenges, Neil planted more bigleaf maple saplings on other flood-prone areas of his land. He looks forward to continued production despite what many would consider unfavorable conditions.
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