Across the world, and with each passing year, more communities are becoming more educated on the value tree populations have on their environments. As a result, organizations are formed, council is held, and education programs are established. Harris County, approximate to Houston, Texas earlier this month created a new edge on the more widespread theme of bolstering the urban tree population. Their solution: make it a competition!

Over the course of two and a half hours, 20 teams convened at the Flood Control District’s Hollister Stormwater Detention Basin, and planted over 2,000 new trees on the banks.

“This basin has gone from being almost bare to a thriving, developing forest,” said Nic Griffin, the Harris County Flood Control District’s Tree Planting and Establishment Coordinator.  “The Houston Area Urban Forestry Council’s Annual Tree Planting Competition has brought great things to this basin as well as several others in Harris County. We appreciate all of the volunteers who take time out of their busy schedules every year to make this happen.”

With this year’s event being the 9th Annual Tree Planting Competition, the benefits and success of the trees planted in 2014 and 2015 were amply evident. Most of the 2014 trees were at least twice their original size, and the 2015 trees were not far behind in health and growth rates.

As reported in last week’s online news release, “The Flood Control District provided pines, oaks, elms, bald cypress and other species for the 9th annual competition, which took place at the Hollister Basin, just south of White Oak Bayou at the intersection of West Little York and Hollister roads. The 11-member teams completed in professional, amateur and student divisions to see which team could plant 100 trees in the shortest amount of time – using only hand tools.”

The new trees, which come from its own tree nursery since 2003, “will help prevent erosion, improve water quality, decrease maintenance costs and beautify the Hollister basin, one of more than 130 stormwater detention basins in Harris County maintained by the Flood Control District.” Tree species are selected from the 6,000-10,000 trees in varying states of maturity and growth housed by the nursery.

“With more than 1,500 bayous and creeks totaling approximately 2,500 miles in length, the Flood Control District accomplishes its mission by devising flood damage reduction plans, implementing the plans and maintaining the infrastructure.”

The benefits of trees in urban areas are now well established, with urban greening high on the agenda for councils across Australia. Of course, enabling trees to thrive in cities has always been challenging, with hardscaping, underground infrastructure, overhead obstacles, and pollution to contend with.

Another challenge that is only now emerging is the importance of good quality soil, and enough of it. Warwick Savvas writes, “Urbanisation historically involves a process of removing topsoil and replacing it with sub-soil and concrete. Sub-soil does not have the necessary chemical and physical properties to support plant growth. Plants need the correct structure to not only physically support them, but also allow essential biological processes to occur.

This includes air gaps in the soil, sufficient availability of water, and the presence of minerals. Healthy soils also need to have organic matter and other elements such as nitrogen and phosphorus to provide nutrients for growth. Then there are the active microbial constituents of top soil. These are the fungi and other living biological creatures that synergistically interact in the soil with the plants to enable exchanges between the soil, water, nutrients, and roots. Sub-soil does not have these properties and will not support plant growth.”

Recent research conducted by Tree Preservation Australia concluded that the standard specified topsoil does not have all the necessary properties to promote healthy trees. Furthermore, soil health is deteriorating further because of compaction, low moisture, toxicity, pollution, and root zones devoid of microbiology.

Matthew Daniel, of Tree Preservation Australia, believes we need to take a new approach to urban soils, stating, “Plants play a pivotal role providing energy to the microbial life in the soil and indirectly to all other life forms. The soil‐plant root associations are based on the complex interactions of uncountable microbes. Each go to ensuring the plant can continue its important role of maintaining healthy growth to then in return provide the nourishment the soil biological network needs to flourish.”

Considerations include enough microbes in the soil, balancing the correct ratios of air space, water, minerals, and organic matter, and lastly ensuring that trees are not planted too closely together.

Daniel concludes, “Understanding and better managing soil and plant microbiology represents a powerful tool which people can learn to apply to great advantage in building healthier soils, plants, animals, people and landscapes.”

To find out more about urban soil solutions, click here.

Source: Sourceable

Image Source: Cornmeal Parade

In Sydney and Canberra, plans for new light rail projects are forging ahead, designed to ease traffic congestion and improve accessibility. While this is no doubt a great thing, concerns are growing as a significant number of mature urban trees are likely to be impacted.

Just recently, a row of historic fig trees was cut down along Anzac Parade in Sydney, making way for a new light rail. Louise Boronyak, Senior Research Consultant at the University of Technology Sydney, writes, “The challenge of retrofitting transport systems into an established urban fabric means difficult decisions are inevitable. But what if building these new transport systems actually leaves parts of our cities more vulnerable to even bigger challenges, such as climate change?

“In Canberra, the ACT government is set to remove approximately 860 trees. In Sydney, about 1277 mature trees will either be removed or have their canopy or roots pruned. Of the condemned trees, 871 are classified as trees of significant value. These trees, some of which were 160 years old, provide an array of benefits that make our cities liveable. These include clean air, amenity, biodiversity and cooling in hot temperatures.”

With trees creating their own microclimates, reducing ambient temperatures, the scary reality is that removing urban trees today will mean the cooling benefits will be lost for at least another 20 years. Of course, this relies on replacement plants being planted in the first place and then surviving to maturity.

Boronyak concludes, “As someone who works in the area of climate change adaptation, I can see how the loss of these trees will have major environmental, economic and social consequences. As a local resident who has walked and cycled daily under the trees, the loss has a personal cost. It is imperative that we find better ways to balance the needs of growing city populations, while ensuring the protection of the natural environment we ultimately rely on to survive.”

We’ve all driven through congested interstate road work, and the landscape is a series of orange cones, equipment and rubble. The result is a smooth blue-black asphalt stretch of road, but in Seattle, their 277 mile-long Interstate 5 could possibly be on its way to becoming something more – actual green landscape.

Originally built in 1962, Interstate 5 quickly became a disruption to the community, and sliced through Seattle’s downtown, “creating not only an eyesore but an abundance of noise and pollution.” Though the problem has been evident for years, it is not until recently that local firm Patano Studio Architecture has proposed an innovative solution brimming with benefits: “Capping the freeway with a two-mile-long, 45-acre elevated park that would hide the roadway and offer space for affordable housing.”

The Seattle C.A.P.itol Hill Park would start, “at the Lakeview overpass on the north end, running along the western edge of Capitol Hill towards the downtown core.” The park would eventually wind its way around to a proposed hybrid arena with the potential to support 20,000 people.

Architectural Digest’s Nick Mafi reports, “By covering the ten lanes of traffic with a park including pedestrian paths, bike lanes, ample green space, and affordable housing, Seattle could set an example for other cities. Los Angeles is currently looking into ways to cover parts of Highway 101, while Boston officials want to cap a section of Interstate 90.”

Mafi further makes a valid, poignant observation, “The new park space could also fill a major urban need missing from Seattle today: A large central downtown park.”

Scott Bonjukian wrote at the Urbanist, “The Center City … is now so intensely developed that there are few vacant sites left for new buildings. But growth will continue for the foreseeable future, and the unused airspace over Interstate 5 will inevitably beckon developers and city planners.”

As with any large infrastructural project, this solution will take time to be fully executed, but simply by beginning the transformation, the momentum, support, and interest from natives and observing cities alike will come.

See more about Patano Studio’s C.A.P.ITOL HILL PARK concept here.

Photography by Pantano Studio