Fallen Leaves – A Nuisance or Treasure?

Fall is here – look at that beautiful foliage!


Leaves 2

While we love to appreciate the wonderful colors of the fall foliage, the one thing that often accompany it – the fallen leaves, is another story. “What a nuisance!” – we might think.  With the thought we might just pick up the rake and bloom, sweep them together, pile them up, then dump them away as garbage. We have been doing this for so long we never thought second time about it.

But is this right?

Actually, the best place for those leaves to go is not garbage, but where they fall on – the earth, or soil, to be more precise.  This is what nature has been doing for millions of years.  It is the nature’s way of keeping everything alive and well.

Learn from nature

If we go to a forest, when we set our sight on its floor, we might see a thick layer of leaves, accumulated over many years.  Nobody cleans them away; the leaves just keep falling and sitting on the older leaves, year after year.  Over the time, those leaves at the bottom will be absorbed into the soil.

Fallen leaves are an excellent source of organic matter for the soil.  With the help of all the living things in the soil, including macro (worms etc.) and micro organisms (bacteria, etc.) in the soil, they will be broken down and transformed into nutrients for the plants.  The soil with the abundance of such nutrients is called black gold.  These kind of soil is:

  • very fertile and great for plants growth.  They are full of the nutrients, moisture, minerals and other matters that plants need for their growth; plants grow faster, taller and healthier with such soil;
  • holds more water.  this kind of soil is a great environment for all kinds of macro and micro organisms.  They improve the soil structure and make the soil like a sponge with many tiny holes.  This kind of soil can retain a large amount of water, making it more drought resistant.  If we have such soil in our garden, watering can be reduced by quite a bit.

In California, where drought is a constant threat, while all kinds of solutions are being explored, healthy soil, with its water holding capacity and implication for water usage reduction, can be an important part of the overall solutions.

  • can absorb more carbon.  In addition to water, soil also holds air, with a big part of that is carbon.  Plants take in carbon dioxide and water, and transform into sugars and oxygen in the photosynthesis function.

Healthy soil can also hold more carbon.  As we are facing the  climate change, which the carbon dioxide is the culprit, it turns out, soil can also play an important role for fighting climate change.   According to Nature Conservancy, “Healthy soils can help reduce the impact of climate change by storing (or sequestering) up to 10 percent of the world’s carbon dioxide emissions. But, if soils are managed poorly or cultivated through unsustainable agricultural practices, soil carbon can be released into the atmosphere in the form of carbon dioxide, which can contribute to climate change.”

From the above, we can see how important healthy soil is for us, and fallen leaves can be one of the keys to achieving it!  Fallen leaves is something that healthy soil needs and badly craves.  In stead of dumping the leaves away, we can try following.

Use fallen leaves the right way

These are the great ways to use the fallen leaves in your home:

  • Mulch your yard with leaves.  This can provide two benefits at the same time: give soil the organic matter, and suppress the growth of weeds.  No need to shred the leaves – they can be worked into the soil fine.  If you prefer, you can shred them before mulching.

fallen leaves

  • Compost.  Leaves are an excellent source of compost materials.  Put them into a compost bin, add food scraps and others (water, etc) with the right ratio, and let the compost process begin.  After about two months, you can get good compost soil that you can apply to the plants.
  • Put them in a yard waste bin.  If your city has a yard waste collection program, put them in the specific bin.  The leaves in the bin will be sent to a compost facility instead of  a landfill.  This way you can help avoid the pollution in a landfill, and turned them into compost – something good for us.
  • Avoid using the leaf blower.  They make noise and carbon dioxide, something we don’t need more of!  If the leaves can’t be left on where they are (remember they make excellent mulch and contribute to great soil) and must be collected, just use a rake or bloom.  Enjoy the foliage while you rake.


















Apple Park – a Spaceship and 9000 Trees

On Sept 12, Apple announced the launch of iPhone 8 and other products at its new Steve Jobs theater, which is part of the brand new campus Apple Park.  While the world finally got to see the next generation of iPhone and other hotly-anticipated products, it also got a glimpse of the near complete Apple park, a project that has been in the works since 2014.

Apple Park

Apple Park sits on a 150 acres lot , 1 mile from its current headquater in Cupetino, in the San Francisco Bay Area.  It  is the brainchild of the legendary Apple co-founder Steve Jobs, a legacy project of his.  “I want to leave a signature campus that expresses the values of the company for generations.”   (Walter Isaacson, Steve Jobs, p.535).  Everyone were curious to find out: how would this be achieved?

Spaceship, and 9000 trees

The most famous part of the Apple Park, of course, is the unique shape of its office building.  As Steve Jobs said, “It’s like a spaceship has landed.” Creative, high tech, cutting-edge, futuristic… a very fitting image for the world’s most valuable high tech company.


Is the spaceship the only major feature of the Apple Park?  No.  If one takes a walk around Apple Park, he will see lots and lots of green – the campus is fully surrounded by trees and plants, not just inside, but also outside of the fence that separates the campus from the rest of the city.

Apple Park 2

Apple Park 3

Why all this green?  Two obvious answers will jump to one’s mind: beautifying the campus, and privacy.  Sure.  However, there are some deeper reasons.

According to “Steve Jobs” by Walter Isaacson, “One of his (Steve’s)  lingering memories was of the orchards that had once dominated the area, so he hired a senior arborist from Stanford and decreed that 80% of the property would be landscaped in a natural manner, with six thousand trees.   ‘I asked him (the arborist) to make sure to include a new set of apricot orchards, you used to see them everywhere, even on the corners, and they’re pare of the legacy of this valley. ‘’’  (p.536)

So the trees and plants here are not just to to green up the space, but to serve two other very important purposes: to honor the legacy of the area, and create an environment that will look like the natural landscape around here.

Steve Jobs liked to walk at Stanford Dish, a trail around a large satellite dish with views of rolling hills that make up the valley.  He admired the hundreds of live oaks there so much that he asked his people to track down the arborist who planted them, and hired him to be the senior arborist of the new Apple Park.  As Steven Levy of Backchannel said,  Jobs “wanted to create a microcosm of Silicon Valley, a landscape reenactment of the days when the cradle of digital disruption had more fruit trees than engineers. In one sense, the building would be an ecological preservation project; in another sense, it’d be a roman a clef written in soil, bark, and blossom.”

A view on Stanford Dish; the dish can be seen on the left

The result is a 150 acre campus that is 80% landscaped, with fruit trees, Califonia natives, and drought tolerant plants from other regions.  The campus now has 9000 trees, 50% more than Jobs’ original number.

Bring back the “Old Valley” with California native plants

Just from the outside, one can see how Jobs’ vision is being realized.

Here, you can see lots of oak trees.  Per Re-Oaking Silicon Valley, “In Silicon Valley, oak ecosystems were the defining feature of the landscape before large-scale transformation. Oak savannas and woodlands were so extensive that the valley was christened the Llano de los Robles, or Plain of the Oaks, by early explorers.”  While we are far away from that now, these oak trees and others can bring us one step closer to it.


Here, you can see oak, strawberry tree, and perenials of yarrow and Douglas iris, all “big” California natives.  All of them adpat well to California’s mediterrian climate, very drought tolerant and hardy.

Douglas Iris is a beautiful plant native to California coast.  They bloom in spring, with purple blue flowers amid long green leaves.

Apple Park 4

Manzanita, another big California native


Seaside Daisy.  You can find them at many coastal locations.  They thrive in windy, cold and dry environments, with all the pretty purple blossom.

Seaside Daisy

California Lilac

All these California native plants not only render the campus a beautiful place, but help bring back an old valley that existed before the transformation.  What is more, since they are all drought tolerant, much less water is needed, helping to conserve  a large amount of water .

When we are planning our own gardens, we can borrow a page from Apple, to build very water efficient yet pretty gardens with mostly native and drought tolerant plants.  If you replace your lawn with a water efficient garden, you may receive rebate by removing the lawn and putting in water efficient plants now ($1 per square feet if all requirements are met).  Find out more about the Santa Clara Landscape Conversion Rebate Program here.

Irrigate trees with recycled water

While most plants are native and only need a little water once established, when they were just planted, they still need quite some water to settle.  As we can see, all the trees and planting areas are equipped with automatic irrigation, receiving regular watering.

9000 trees on the campus need a lot of water.  To address this need, Apple planned something well ahead.  It partly funded a project to lay pipes and bring recyled water to the campus.   Per Jordan Kahn of 9to5mac.com, “Apple catalyzed talks among the various water stakeholders in the area, making plain its desire to use recycled water on its new campus, said Katherine Oven, deputy operating officer of the water district… ”Apple drove this project,” she said. ‘It really is a true partnership of both public and private agencies.’”  The project finished in late 2016, in time for most of the trees and plants’ arrival.

By using recycled water, Apple can further reduce its net water usage, conserving more water.  In a world where water the resource just keeps getting more scarce relative to our demand, recycled water has become a bigger and bigger part of the overall water strategy.  How Apple waters its vast campus sets a good example.

Benefits of Trees

Trees can provide many benefits in addition to honoring a place’s legacy.  They can

  • Improve air quality by reducing pollution and filtering out a big portion of the fine particle pollutants, and noises.  In places with many trees, the air just feels more fresh and the environment quieter.  In a city like Tokyo, although it has a population of over 9 million people and heavy car traffic, abundance of trees and vegetation must have played a big role in making it very clean (air) and quiet.
  • Reduce stress.  Last year a study found that simply looking at trees can reduce your stress.  If one gets more active by taking a walk or jog in the trees, the health benefit can be more significant.
  • Cool down the environment during hot summer days and reduce air conditioning energy and cost.  While we are having more and more heat waves and extreme hot weathers in summer, the cooling effect of the trees have become ever more important.  By reducing the energy required for air conditioning, we can further cut down the green house gas and its warming effect.
  • Increase biodiversity.  A big tree like an oak can support a big ecosystem, with all kinds of insets, birds, small animals such as mouses and squirrels, as well as the plants that have been living close to it for tens of thousands of years.  Each ecosystem can contribute to the health and richness of the much bigger ecosystem of the whole area.
  • Manage storm water and reduce the hazard of a flood.  During storms trees can absorb a large amount of water, reduce runoff, reduce the speed and power of the rainfall, thus reduce the hazard of a flood in the city.

With all these benefits and more, it is easy to see why we should plant more trees.  At office parks, at our own gardens, in the streets and parks.  Include a tree or two when planning a water efficient garden.

Office and Trees: Yin and Yang of an Office Park

When Steve Jobs presented Apple Park’s plan to the Cupertino city council, he said, “I think we have a shot at building the best office building in the world.”

On the one hand, the Apple Park has a building in the very bold and creative shape of a spaceship; on the other, 9000 trees that take up 80% of the space.  One is for innovation, technology, and products; another is for environment, nature, beauty, and inspiration; one eyes the future, the other ties to the place where we come from.

The building and trees are like Yin and Yang for Apple Park.  Together they make this environment where people want to absorb the best the nature offers, and create the best technology and products in return.



How Does Tokyo Make Its Space Green

We all know how important it is to have trees and plants in the cities.  They absorb carbon dioxide, produce oxygen, filter harmful particles from the air, lower temperatures – just to name a few.  With population growth and climate change, it is more important than ever to have more trees and greenery in the city.  Tokyo, with a population of over 9 million, is one of the most populous cities in the world.  How does Tokyo make its city green?  Some observations from a recent visit provides some interesting lessons.

Create more space for plants

In big cities, every inch of land is valuable.  Everyone wants more trees and green, but where to plant them?  Well, turns out, if you can’t do it on the ground, you can do it elsewhere.  Take a look…

In an office building

In this building, you don’t see a glass wall at second and third floors, instead you see…trees!  Yes, trees, tall and dense as they block out most of the outer spaces at these floors.   Only from the 4th floor up will you see the glass walls .  This is a green building, literately.

a green building 1


a green building 2

On the wall

This is a big train station, with a bullet train station inside.  The foot traffic can be heavy.  Look at this stair – the wall is completely covered by plants.

a green wall under a stair

Opposite the station entrance, is another wall, also covered by plants. Over the wall is a busy boulevard with heavy traffic, but you almost can not feel it, as here on this side all you feel is quiet and comfort.

a green wall

On the base of a flower bed

Not just a flower bed, but one with a green “skirt”?  Nice.  Planting at the base of the flowered bed adds more plants and green to the space, enhance the view, make the air fresher and environment quieter.

a green flower bed

A space of trees doubles as…

In Tokyo, trees don’t simply line the streets, they are used in quite some other ways.  Here a space with trees and plants is used as…

A rest station

This space is in front of a shopping plaza, just off a busy boulevard in Ginza, Tokyo.  Here the colorful sitting blocks in the trees and plants provide a perfect rest area for shoppers and people who walk by.

a rest station

A part of art

You will find this beautiful view at a street corner right across an entrance of the Imperial Palace and the moat surrounding the palace. Here, the tree is the centerpiece of this very elegant piece of art. According to the information bulletin, “These camphor trees (ones shown in the photo) have been on the site since the 1970s, long pre-dating the construction of the building.  During construction they were planted elsewhere, and then replanted…as a symbol of the building.” The 2 jade boats on the water is a throwback to the days when “Tokyo was once a city where boats piled the moat as a waterway”.  Trees here have become an integral part of the environment, and history.

a tree as the centerpiece

At the train station shown above, the green wall is like a piece of art too. Look at the all the greens of different shades, heights and textures.

a green wall 3

Bicycle Friendliness

Tokyo is a city quite friendly for bicycles.  In some parts of the city, the bicycle lane is not in the streets, but on sidewalks.  The bicycle and pedestrians lanes are distinguished by the different colors on the floor – red for pedestrians and grey for bicycles.  It is safe and easy to ride a bicycle here.

bike lane on sidewalk

There are parking areas for bicycles on the sidewalks, near a train station, etc.

bikes in Tokyp street

Using bicycles, instead of cars in a city can reduce carbon emissions, help with the air quality and reduce the heat island effect.  Facilities like these make it easy for bicycling to be a way of life.

In summary, while Tokyo is a big metropolitan city of over 9 million people, aboundance of trees and greenary makes it a much cleaner (air) and quieter city than you would imagine for such a big population.  Trees are critically important for a city’s environment, we can plant more of them in the place we live in too – in the streets, parks, and our gardens.


Trees – Great Managers of Stormwater

Rains and storms have been sweeping California for the last couple of months, making 2017 a big wet year.  While this is so great,  relieving the state’s historic, 5-year drought, and lifting half of the state out of drought, now we face another issue opposite the drought: stormwater runoff, and in some places, flood and mudslide.  Due to mudslide, some free ways in North Cal have to be closed.

Stormwater Flood

How can we better manage stormwater and reduce the hazard? One of the key answers lies in something we see all the time – trees.

Trees Reduce Runoff by Drawing a Large Amount of Stormwater

For their critical function of photosynthesis and other functions, trees need a lot of water.  They take water from soil, finish the processes,  and evaporate it into air.  Each tree is like a sponge that absorbs away a large amount of rainwater that sinks in soil.

In addition,  the branches and leaves of trees, like arms and hands, can catch and absorb a big amount of raindrops falling from sky, reducing that falling on ground.

As trees draw away so much rain water, they reduce runoff.

Trees Draw Water

Trees Reduce Soil Erosion By Slowing Down Rainwater

The canopies of trees can slow down raindrops falling through them significantly, reduce the force they hit the ground; On the ground, trees block and slow the current of stormwater, reducing its force to carry soil; underground, the roots of trees bind soil tightly so they are not as easily washed away. All together, tress lessen the impact of rainfall for soil, effectively reduce erosion and mudslide.

Trees Reduce Erosion by Stormwater

Trees Improve Quality of Soil and Increase Storage Capacity for Water

The root systems of trees break up the soil, create space for air and water, support the growth of living organisms and worms; the fallen leaves, and the waste of animals live in the trees further add to the organic matters deposited onto the soil.  Together they improve the quality of soil, and its capacity to hold water.

According to USDA, “Each 1 percent increase in soil organic matter helps soil hold 20,000 gallons more water per acre.”   When the heavy rains come, healthy soil helped created by trees can absorb much more water than barren soil, reduce runoff and its hazard.

Trees Increase Water Holding Capacity

Trees Transform Pollutants Into Less Harmful Substances

From the long course that stormwater flows over, especially in cities, it usually carry a certain amount of pollutants, such as metals, chemicals, etc.  When trees draw water from soil for its photosynthesis and other functions, they also draw pollutants with it.  After the processes, these pollutants are transformed into less harmful substances, and delivered to all parts of trees.  Trees are natural purifiers that filter out the harmful substances, making water and environment for us cleaner and safer.

Trees Transform Pollutants in Stormwater

Include Trees In Water Efficient Gardens

Trees have always been an important part of water efficient gardens. In dry times, along with native and drought tolerant plants, trees can beautify the landscape, cool down the area, reduce demand for water, improve soil quality and enhance overall capability of water conservation. In rainy season, as trees are such great stormwater managers, they can help the community reduce runoff and loss of soil.

Quite a few popular trees, i.e., Crape Myrtle, Fig, Avocado, Pomegranate, etc, which qualify for Santa Clara Water District’s Landscape Conversion Rebates, are good choices to be included in a water efficient garden.  With such a tree in your garden, not only will you enjoy its shade and fruits, but also that great feeling that they are strong helpers in rainy season as well as dry.

Trees In a Water efficient Garden