Tree

===Ornamental trees===
{{main|Ornamental trees}}
Trees create a visual impact in the same way as do other landscape features and give a sense of maturity and permanence to park and garden. They are grown for the beauty of their forms, their foliage, flowers, fruit and bark and their siting is of major importance in creating a landscape. They can be grouped informally, often surrounded by plantings of bulbs, laid out in stately avenues or used as specimen trees. As living things, their appearance changes with the season and from year to year.<ref>{{cite book |title=The Royal Horticultural Society Encyclopedia of Gardening |editor-last=Brickell |editor-first=Christopher  |year=1992 |publisher=Dorling Kindersley |chapter=Ornamental trees |isbn=978-0-86318-979-1 |pages=32–33}}</ref>

Trees are often planted in town environments where they are known as street trees or amenity trees. They can provide shade and cooling through [[evapotranspiration]], absorb greenhouse gases and pollutants, intercept rainfall, and reduce the risk of flooding. Scientific studies show that street trees help cities be more sustainable, and improve the physical and mental wellbeing of the citizens.<ref>{{Cite journal |last1=Turner-Skoff|first1=J. |last2=Cavender|first2=N. |title=The Benefits of Trees for Livable and Sustainable Communities |journal=Plants, People, Planet  |volume=1 |issue=4 |pages=323–335 |year=2019 |doi=10.1002/ppp3.39|doi-access=free }}</ref> It has been shown that they are beneficial to humans in creating a sense of well-being and reducing stress. Many towns have initiated tree-planting programmes.<ref>{{cite web |url=http://www.forestry.gov.uk/fr/urgc-7EKEC8 |title=Street trees |work=Greenspace initiative |publisher=Forestry Commission |access-date=20 September 2014 |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304110933/http://www.forestry.gov.uk/fr/urgc-7EKEC8 |url-status=live }}</ref> In London for example, there is an initiative to plant 20,000 new street trees and to have an increase in tree cover of 5% by 2025, equivalent to one tree for every resident.<ref>{{cite web |url=https://www.london.gov.uk/WHAT-WE-DO/environment/parks-green-spaces-and-biodiversity/releaf-partnership |title=The RE:LEAF Partnership|work=Greening London |publisher=Mayor of London |access-date=20 September 2014 |date=10 August 2015 |archive-date=24 April 2016 |archive-url=https://web.archive.org/web/20160424163422/https://www.london.gov.uk/what-we-do/environment/parks-green-spaces-and-biodiversity/releaf-partnership |url-status=live }}</ref>