NOT removing fallen leaves and twigs
It is customary to think that fallen leaves constitute an undesired element in public and private green space – they are not aesthetically pleasing and they are regarded as a breeding ground for diseases and pests which threaten plants. As far as removing fallen leaves from the strips of land adjacent to roads, paths or park lanes is advisable, removing them from under trees and bushes has an adverse effect on the condition of soil and tree health. If we are obliged to remove leaves from roads and paths, it is important to choose non-invasive methods, i.e. sweeping them with a broom or raking. The leaves collected in this way may be left under the trees or placed in a composter. Putting leaves into plastic bags (even biodegradable ones) is as harmful for the environment as it is aesthetically displeasing. Decomposing leaves constitute a natural source of humus and retain water in the soil for longer. The minimum decomposition period of leaves in our climate is three years. The process may be accelerated using an organic fertiliser (e.g. from a communal composter). Bedding and freshly fallen leaves will attract small animals, which will be able to feed and spend the winter there. Among them are legally protected European hedgehogs and all  types of shrews, as well as many types of insects.
To raise the attractiveness of the area, it may be a good idea to introduce shade-loving groundcover plants, such as ivy or ferns. After two or three years, such an area will practically not require maintenance, apart from periodical checks and possibly removing seedlings of trees. Moreover, most of these plants provide natural benefit to bees. It is also useful to plant bushes around groups of trees, as they will stop leaves from spreading in strong winds and will provide home to birds, many species of small mammals and insects, thus increasing the area’s biodiversity.

NOT mowing lawns
A lawn which gets mowed less frequently will retain water in the ground for longer and will create good living conditions for small organisms. It is particularly important in the summer, when excessively cut grass almost immediately dries, revealing equally dry ground and contributing, along with the rapidly heating anthropogenic infrastructure (concrete pavements, tarmac roads), to increasing the air temperature in the city.

Wildflower meadows
Wildflower meadows are a good alternative to traditional lawns as they are easy to maintain and do not require regular watering or fertilising. It is enough to mow them once or twice a year, preferably in late summer or in autumn. They increase biodiversity in the city and the deep and extensive root systems of many types of wild flowers make them more resistant to drought and also fertilise the soil through the bacteria living on the roots. Wildflower meadows support pollinators such as bumblebees, butterflies, and solitary bees. Thus, they can save time, energy and resources, while simultaneously adding aesthetic qualities to the local environment.

You can read more about the benefits of wildflower meadows on the website of Fundacja Łąka.

Composters
Composters in parks are introduced at many Polish cities and municipalities. They are also popular among residents associations and housing cooperatives. You can find out how to make your own composter here.

Caring for the wellbeing of urban plants and animals
When you organise events in green areas, remember to respect their non-human residents. Loud noise during open-air concerts scares off all urban animals, especially birds. Excessive lighting (the so-called light pollution in the cities) changes circadian rhythms of animals. When making an outdoor installation, erecting temporary architecture or installing sculptures or objects, remember not to intervene excessively in the natural plant structure but rather try and adjust to it.