What is a Tree Island, and how does it help with Carbon Storage?

Oct 18, 2022

The Everglades in southern Florida are also known as a reserve of carbon storage. Some areas of the Everglades have “tree islands” and a recent study showed they are capable of storing more carbon and other nutrients than their marsh neighbors. The Soil Science Society of America’s (SSSA) October 15^th Soils Matter blog explores the findings of a recent study about tree islands that was performed by Florida scientists.

The Everglades contain a diverse set of habitats, including prairies and mangrove swamps. Other areas of woody vegetation embedded within the marsh landscape are known as tree islands. The variety of trees can vary from willows to cypress to various hardwood varieties.

The Everglades is a managed area. Water flow is controlled through a series of canals. Stormwater treatment areas were constructed in the 1980s to control damage from stormwater surges. There are three areas that scientists are currently focusing on to determine best practices within the Everglades:

sediment control best management practices.
nutrient management control best management practices.
water management control best management practices.

The current study by a group of scientists at Florida International University researched whether tree islands were less affected by changing water levels than neighboring marshes.

To study the soil, the researchers took “soil cores.” They place long tubes into the soil and pull them out, to capture the soil composition at various depths. Tree islands’ soils were composed of low-organic peat, heavy peat, and peat soils. These types of soil store large amounts of carbon in our ecosystems throughout the world (including cold areas like the arctic and subarctic).

The study found that tree islands could store nearly five times more organic matter (carbon) than marshy areas. They could store over twice the amount of nitrogen. Finally, they stored almost six times the amount of phosphorus.

The authors attribute these observed differences in nutrient storage capacity between the marshes and tree islands to two factors. First, the quality and quantity of litterfall and root biomass between marshes and tree islands are different. The leaf litter from marshes decomposes faster than leaf litter from trees. And the relationship between the roots and soil microbes differs, too. This allows for more nutrient buildup in the tree islands.

Click here to see more...

Video: Turning Plant Defense Into a Management Strategy

Turning Plant Defense Into a Management Strategy

Understanding how a plant responds to stress is one thing.

Using that knowledge to make better management decisions is another.

Systemic acquired resistance, or SAR, is the plant's more direct defense response. When stress or infection occurs, the plant begins signaling throughout its system and preparing defensive compounds.

But if we know that response exists, can we help prepare the plant before the stress arrives?

The answer starts with understanding what triggers the response and what the plant needs to carry it out.

The Trigger and the Fuel

Salicylic acid plays an important role in triggering the SAR pathway.

Think of it as turning the truck on.

The engine may be running, but it still needs fuel to do the work.

In this case, manganese plays an important role in supporting the enzyme systems involved in the plant's defensive response.

This makes manganese status an important part of the conversation. Whether a producer is using tissue testing, sap analysis, or simply scouting for visible deficiency symptoms, the goal is to make sure the plant has adequate manganese available.

Manganese is required in relatively small amounts, but that does not make its role small.

If the plant receives a signal to defend itself but lacks the nutrition needed to support that response, it may struggle to carry out the process efficiently.

The trigger matters.

The fuel matters too.

Prepare Before the Stress Arrives

The best time to think about stress management is before the plant is overwhelmed.

Once a crop is already struggling, management can quickly turn into a game of catch-up.

This is similar to nitrogen management. Once a plant becomes severely deficient, correcting the problem does not necessarily erase the time and yield potential already lost.

Plant defense can work the same way.

Low-rate, targeted approaches designed to support the SAR pathway may fit best ahead of an expected stress event rather than after significant damage has already occurred.

That requires producers to think about predictable stress.

We may not know exactly what the weather will do tomorrow, but we generally know summer heat is coming. We know certain field conditions increase disease pressure. We know a herbicide application can temporarily stress a crop as the plant processes the chemistry.

Even a properly timed and labeled herbicide application can create a temporary response in the plant.

That does not mean the herbicide is bad.

Weeds can create significantly more yield loss than the temporary stress caused by controlling them.

The question is not whether we should eliminate every stressor.

The question is whether we can better prepare the plant to manage necessary and predictable stress.

Not All Stress Is Bad

Stress is a normal part of plant growth.

A perfectly stress-free environment does not exist in the field.

In fact, some stress is necessary for normal plant development. A plant responds to wind, temperature, moisture, sunlight, and countless other environmental signals throughout the season.

The environment is stress.

The plant's job is to manage it.

Problems begin when the stress load becomes greater than the plant's ability to respond.

Extreme heat, drought, high salt concentrations, disease pressure, and even certain management practices can add to that load.

This is where understanding SAR becomes useful.

Instead of waiting until the plant is visibly struggling, producers can begin identifying periods when stress is likely and make management decisions around those windows.

ISR Starts With the Soil

While SAR is a more direct defense response, induced systemic resistance, or ISR, brings the conversation back to soil health.

The longevity of a farm is closely connected to the health of its soil.

Carbon plays a major role because it supports biological life within the soil. Bacteria, fungi, and other organisms interact with plant roots and influence how the plant grows, accesses nutrients, and prepares for stress.

This is why soil health cannot be reduced to one product or one application.

It is a system.

Keeping living plants in the field longer can support biological activity. Cover crops may fit some operations. Better water management can improve soil conditions.