1. Jeffrey pine (Pinus jeffreyi). This large tree can grow to 120 feet. The gray-green needles are in bundles of three and 5-10 inches long, and its resin has a distinct lemon or vanilla scent.

2. Tree stump. A tree stump can tell you a lot about the way trees grow. The stump has many tree rings under the outer layer of bark. The tree forms one ring every year. So by counting the number of rings, you can figure out how old the tree was.

   Tree rings can also tell you about the weather in the years that the tree was alive. When there is plenty of rain and sunshine, the tree grows faster and the rings are further apart. Scientists study tree rings to learn about the weather from long ago.

   What causes tree rings? In the middle of the tree stump, you can see a core of soft spongy material called pith that formed when the tree was just a sapling. Around the pith is dark dense wood, which is called the heartwood. The annual rings are from when the tree was very young, and the rings can be so close together that they are hard to count. Next is the sapwood, lighter-colored wood with a smaller number of rings. Outside of the sapwood and under the bark is the phloem.

   A layer that is so small that it is very hard to see is the cambium. The cambium is very important because it is the part of the trunk that is growing. The light-colored wood is formed in the spring and the darker colored wood is formed later in the growing season.

   The sapwood is responsible for moving water and nutrients from the roots up to the leaves. In turn, the phloem transports the food, mostly sugars, made by the leaves, to the trunk and roots. As the tree grows, older rings of sapwood gradually fill with a hard substance, called lignin, and become heartwood.

3. Lavender (Lavandula sp.). The lavenders include 25-30 species and are members of  the mint family. The scent of the lavender makes it attractive for dried flower arrangements and potpourris. The scent comes from an oil, which is used as an antiseptic. The flowers also yield a lot of nectar that is used by bees to make very good hone

4. Agapanthus (Agapanthus sp.). The plants have funnel-shaped bluish flowers. Each stem has many flowers. Agapanthus grow from bulbs or seed. The bulbs can be “separated” to produce new plants.

5. Rosemary (Rosmarinus officinalis). This herb grows year round in Castro Valley. In the summer, it has beautiful blue flowers that contrast nicely with its dark green leaves.

6. Eucalyptus (Eucalyptus sp.). Although eucalyptus trees are very common in the Bay Area, they are not a native California plant. They were brought here from Australia in the 19^th Century. The reason they were brought over is unclear, but now they are used as windbreaks and as decorative plants. These very tall trees also produce a lot of oil (thus, their distinctive odor) and burn rapidly. The bark is very interesting. It dies annually. In some species, the bark falls off. In others, the bark stays on the tree and dries out.

8. Conifers and deciduous trees. Trees have evolved various strategies to survive, and some of these can easily be seen in the park. First, conifers, such as pines, spruces, and redwoods, are all conifers. They do not lose their leaves in the winter. They do not have flowers. Deciduous trees have flowers and lose their leaves in winter.

9. Apple tree. Who doesn’t like apples? This natural snack is sweet, but contains no fat, sodium, or cholesterol. And they have only 80 calories.

   Scientists believe that the first apple trees came from what is now the country of Kazakhstan. The first apples in the US were planted by the Pilgrims in the Massachusetts Bay Colony. In the early colonies, apples were known as winter bananas or melt-in-the-mouth. We can easily get several varieties of apples, including Granny Smith, Cala, golden delicious, red delicious, and Fuji. But over 7500 varieties are grown in the world. That’s a lot of apples!

   Botanists gave apples the scientific name Malus domestica). Nearly two-thirds of apples are eaten as fresh fruit. The rest are made into apple sauce, apple juice, and other products. Botanists call apples and pears “pomes” because they have a paper-like core, a fleshy layer around the core (the part you eat), and an outer skin that can be red, green, or yellow.

   And we all know the legend of Johnny Appleseed, who traveled through Ohio, Indiana,and Illinois, planting apple trees for everyone to enjoy.

   Each apple has 10 seeds. The one exception is the Northern Spy, which has 20. In late spring, apple trees display white blossoms. Honeybees collect the nectar in the flowers and distribute the pollen to other trees. Farmers make sure that they have bee hives nearby. 

10. Manzanita (Arctostaphylos sp.). Manzanitas are common native California plants. They have a distinctive look with smooth, orange or red bark and twisting branches. About 60 species can be found, and they range in size from low, ground-hugging species to mountain species that grow to be 30 feet tall. The Spanish word “manzanita” means “little apple,” but fruit of the manzanita is a berry. The berries are eaten by many animals, and even Native Americans used them for food.

12. Bamboo. Bamboo is not native to the United States. It was introduced years ago as a decorative and useful plant. Bamboos are woody perennial grasses. More than 1,000 species of bamboo are known, and they range in size from the very small to tree-like species. Bamboos often grow in very dense clumps. Bamboos and the grasses provide food for a large number of animals. For example, pandas love to eat bamboo. And although most of us in the Bay Area use it to decorate our yards, the tender sprouts of some bamboo plants are used as a vegetable, particularly in Asian dishes.

13. Juniper (Juniperus sp.). Junipers are an evergreen bush with pointed needles and scale-like foliage. There are male and female plants, and only female plants produce fleshy, blue berries. There are hundreds of different varieties of juniper with a variety of sizes and colors. They also have different shapes, including prostrate, spreading, and upright.