After you change the goalPP, select Curve1 and click on your Create Springs button. Now create a Uniform field. Change the settings of the field to Magnitude 4.
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Select Curve1 again and click on your Dynamic Relationships Editor button. Under fields click on uniformField1 so that is is highlighted yellow. You now have a dynamic joint chain that is affected by field.
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Select Curve2 and repeat the process of Creating a Soft Body, Adjusting the particles goalPP. Creating a Spring for the Curve and then Connecting the Curve to the uniform field.
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However we want the leaves to be affected by the wind more than the trunk so adjust the goalPP starting at 1.0 and ending at .1 for the last particle.