Research Question and Hypothesis   


Problem/Purpose

We are a team of four students, Joshua and Tyler from the Indiana School for the Deaf, in Indianapolis, Indiana and Kelsey and Lateefah from the Model Secondary School for the Deaf in Washington, DC. We are working together to study the timing of budburst on Silver Maple and Crab Apple trees to see if there are differences in budburst in the locations of our two schools. One school, Indiana School for the Deaf, is located in Indianapolis, Indiana (Lat: 39.7251, Long: -86.0841). The second school is the Model Secondary School for the Deaf in Washington, DC (Lat: 38.910258, Long: -76.9990639). Our schools are about 500 miles apart east and west, but are close to the same latitude north. From our reading we know that weather will influence budburst. The goal for this project is to study phenology to help us understand the relationship between climate and our trees. We are studying phenology to see the cycle of plant growth and understand the effect of environmental factors on budburst. Phenology is the study of the response of living organisms to seasonal and climatic changes to the environment in which they live. [What is Phenology? 2006]. We know that changes in phenology can affect society such as in species distribution, spread of disease, food production, natural resources, and changing ecosystems. We are trying to test how our two locations are different and learn what controls budburst. We surmise that it is mostly under control of temperature or precipitation. At each school we will study two different kinds of trees (Silver Maple and Crab Apple). Our research question: Is there a difference in tree phenology with regard to spring budding in our two schools, and what environmental factor is (or factors are) controlling the timing of budburst in our areas?

Hypothesis

We predict that we will see a difference in leaf budburst of the two trees at our two schools because Indianapolis is a landlocked city far from any large body of water (about 600 miles west from the Atlantic Ocean, and 150 miles south of Lake Michigan). Washington, DC is about 30 miles west from the Chesapeake Bay and only about 100 miles west from the Atlantic Ocean.

Since Washington, DC is closer to an ocean, we think budburst will happen in D.C. before budburst in Indianapolis. We assume that the buds will burst in the same week each year if temperature and precipitation patterns are similar for the four months before the budburst. Our team could not agree about whether temperature or precipitation controls budburst. Finally we decided to test the idea of precipitation. Our hypothesis is that the tree buds in Washington, DC will burst before Indiana’s, because we think there is more water in the air closer to the ocean, and that water controls the timing of budburst.


Background Information

Before we started our budburst observations outdoors we needed to know something about the buds themselves. We studied the buds under a microscope and enjoyed learning the names of the structures.

Buds – Leaves

Inside the bud that will grow into a leaf are neatly folded immature leaves. Both the immature leaves and stem are in a protective case of the bud scale. When the leaves are ready to open, the bud scale will swell. The axil is where the leaf joins the stem. A node is where the leaf is an appendage of the stem. The axil guides the stem to grow upward. The bud scales function to protect the leaf from the environment while the tiny leaves are still tender.

Buds – Flowers

The flower has reproductive organs for male and female. The female organ is called a carpal while the male organ is called a stamen. Stamens have a filament that supports the anther, which produce the pollen. The carpal has an ovary with a swollen base which will become the fruit and inside of it ovules which will become seeds. The style is an extension from the ovary. The stigma is on top of the style and its purpose is to become receptive and slightly sticky when the ovules are ready to be fertilized. Fertilization happens when pollen falls on the stigma, and moves down through the style to the ovaries. The stigma and style is also known as the pistil. The sepals form the calyx and the whorl of petals which are used for attraction of insects to fertilize the flower. The calyx protects the flower during the bud time period, before the bud starts to grow and mature.

We learned a lot about the biology of the two trees. In Washington, DC, we noticed that there were no seeds in this season for the Silver Maple (Acer) at MSSD, and after reading about the tree we realized that it is a male tree. Our teachers found it out on the Internet which explained that some trees are both male and female and some trees have just one gender on each tree [Discover Life 2007]. When we all talked about this, we then realized that the Silver Maple in Indiana is a female tree because at ISD, we saw no male flowers on that tree. This surprised us and it also surprised our teachers! They said they learned something too. Another thing, we noticed at MSSD, the Acer male flowers did not last long, and the anthers drooped after two days while the Crab Apple flowers lasted about a month, so we are wondering if the female plants will last longer than the male plants. At ISD, we were disappointed because our Crab Apple flowers were damaged by below freezing temperatures about a week and a half after they opened, so our Crab Apple tree was not very pretty.