One essential way to describe your land is to understand how humans use it as well as to assess all visible components of the land surface. These can be, for example, trees, shrubs, water bodies, crops and other plants, buildings, roads, greenhouses and many others.
Observing and describing these elements can help us understand how they affect conditions of your site, such as sunshine, moisture, temperature or overall plant growth. We call these elements land cover classes or layers. Land cover classes are the building blocks for more complex features across larger geographical areas – forests, allotment gardens, crop fields, villages, streets, playgrounds, lakes, backyards, highways, or city parks. They have not only a physical structure but also a specific function for humans, we call this land use (agriculture, transportation, recreation, living, abandoned, etc.).
Identifying land cover classes is important to help understand and be able to compare different sites and landscapes consistently. It allows us to identify similarities and differences between sites.
They can also be helpful for:
- identifying potential microclimates, for example, a pond in summer would create more humid conditions around it. Similarly, a paved area might retain heat in summer but be colder in winter.
- making inferences about soils and nutrients, for example, trees might be growing on deeper soils, but a road would have no accessible soil and hence make water infiltration impossible.
- suggesting animals that we might expect to find associated with a habitat or plant family, or compare levels of biodiversity.
There are many different ways of defining land cover classes. We created a simple list of elements that you can look for during your field observations.
- Trees (fruit and nut trees incl. olives, other broad-leaved and coniferous trees)
- Shrubs (fruiting shrubs incl. grapevines, other shrubs)
- Vegetables and crops, herbs and ornamentals
- Other ground covering plants (weeds, grasses)
- Mulched ground
- Sealed surfaces (roads, buildings)
How to describe land cover
There are different ways to go about describing your land cover. One is to find any spot outside and describe the land cover elements around that very spot. Regardless of how the surrounding area looks like, whether it is different or similar to the spot itself. Another way is to find a spot that is typical – or representative – of the larger area, meaning that whatever land cover elements are found around the spot, will also be found in the same way, or in the same pattern across a larger, definable area. This definable area is called “a parcel”. To describe a parcel, one needs to list the land cover class(es) or other characteristics that are typical for the parcel, as well as the size of the land these characteristics apply to. If you have placed a soil moisture sensor, you will assess land cover around a representative parcel around the sensor.
Simple or complex?
A parcel can have a simple or a complex landcover. A parcel with a simple land cover has one dominant land cover element on it. Dominant means, the type of land cover (e.g. trees, or vegetables) evenly covers most of the parcel, and there are no other obvious land cover elements around (e.g. a forest, a wheat field). If the land cover is complex it is built up of two or more elements (e.g. an olive grove with grass beneath, or a patch with vegetables, herbs, berry bushes, and a few scattered apple trees).
Both of the examples below have a simple land cover: a wheat field with probably around 1 ha and a vegetable patch with roughly 150 sqm (0.015 ha). The big difference between them is the size of the representative parcel.
We consider this example a complex land cover: an olive grove with with grass beneath and approximately 2 ha area.
This way, you should be able to distinguish a parcel from the surrounding landscape or other parcels (e.g. an orchard with grass beneath is different from a neighbouring forest, a vegetable patch is different from an orchard, a corn field different from a fallow, etc.).
Take this quiz to practise matching land cover images with descriptions.