The Trees of Gov­er­nors Island: Sur­vey­ing Our Diverse Canopy


The young trees of Hammock Grove in the foreground, with the older trees of the North Island surrounding Liggett Hall in the background.

Guest post by Mal­colm Gore, Arborist at the Trust for Gov­er­nors Island

In the Win­ter and Spring of 2022, the Trust for Gov­er­nors Island con­duct­ed a sur­vey of all trees on Gov­er­nors Island to bet­ter under­stand the diver­si­ty, health, and longevi­ty of our unique urban for­est. The Trust received a grant from the New York State Depart­ment of Envi­ron­men­tal Con­ser­va­tion in 2021 to com­plete this sur­vey, and con­tract­ed Dav­ey Resource Group, a nation­al­ly respect­ed tree com­pa­ny, to con­duct the sur­vey and cre­ate a Com­mu­ni­ty For­est Man­age­ment Plan for this cru­cial canopy resource sit­u­at­ed in the mid­dle of New York Harbor. 

Why sur­vey our trees? It’s crit­i­cal that we have the full pic­ture of the Island’s tree canopy to make sure we are the best stew­ards we can be, ensur­ing our trees sur­vive — and thrive — for years to come. Gov­er­nors Island is home to almost 3,500 trees (3,496 to be exact) com­pris­ing 123 dif­fer­ent species. Of these trees, 97% are in either fair, good, or excel­lent con­di­tion — mean­ing they will con­tin­ue to pro­vide count­less ben­e­fits to the many human and non-human vis­i­tors of Gov­er­nors Island for years to come. Before div­ing into the spe­cif­ic ben­e­fits pro­vid­ed by our arbo­re­al friends, let’s take a look at the diver­si­ty of this island forest. 

Lon­don Plane Trees, with their dis­tinc­tive white bark and arch­ing branch­es, are the most plen­ti­ful tree on the Island as the 422 indi­vid­u­als rep­re­sent 12% of the total tree pop­u­la­tion on Gov­er­nors Island. They also account for a whop­ping 54% of the total leaf cov­er on the island, since most of them are mature trees that were plant­ed when Robert Moses was NYC Parks Com­mis­sion­er (while we aren’t sure the extent to which he had a say in the trees plant­ed on Gov­er­nors Island, Lon­don Plane Trees sprung up in huge num­bers across the city dur­ing this time peri­od— it seems they were his favorite tree). Hav­ing a sin­gle tree take up 12% of the canopy does come with some risk — if a new dis­ease that affect­ed Lon­don Plane Trees were to sweep through New York, Gov­er­nors Island would lose a lot of its canopy. This dis­ease risk is pre­cise­ly why the Trust is active­ly plant­i­ng many dif­fer­ent native tree species that will make our urban for­est more resilient. 

Com­ing in sec­ond are Swamp White Oaks, with 202 indi­vid­u­als that com­prise 6% of the total, fol­lowed by 150 of both North­ern Red Oaks and Riv­er Birch­es. Round­ing out the top five are the 120 Sweet­gums that call the Island home. These native tree species are vital­ly impor­tant to bird and insect pop­u­la­tions, as many types of cater­pil­lars (AKA baby bird food) feed on their leaves in the spring and summer. 

Addi­tion­al­ly, the major­i­ty of these trees are young and, as they grow and mature, will pro­vide more habi­tat and food for the pletho­ra of fau­na that vis­it the Island every year. 


Photo by Sarma Ozols

Bio­di­ver­si­ty isn’t the only impor­tant thing to con­sid­er when main­tain­ing a healthy tree canopy; the age diver­si­ty of the Island’s tree pop­u­la­tion is also impor­tant. Mature trees pro­vide more habi­tat and shade, but are also riski­er giv­en their greater bulk and sur­face area to catch wind­storms. The below chart rep­re­sents the rel­a­tive age of Gov­er­nors Island’s trees as com­pared to the ide­al to sus­tain a healthy forest.


Age breakdown of Governors Island's trees as compared to the ideal, compiled by Davey Resource Group, Inc.

As you can see, Gov­er­nors Island’s tree canopy con­tains near­ly dou­ble the amount of rec­om­mend­ed young trees — this is large­ly due to all of the trees plant­ed with­in the last five years in the Island’s award-win­ning park space. With prop­er care and time, these young trees should devel­op into estab­lished ones as soon as 2024, and this new urban for­est will become more robust and self-sufficient. 

Cur­rent­ly, only about 91 acres of Gov­er­nors Island’s 172 acres are con­sid­ered shad­ed, and the vast major­i­ty of that is in the Island’s His­toric Dis­trict under those 422 Lon­don Plane Trees. As the young oaks, sweet­gums, and birch­es grow and mature on the South Island, more of the Island will expe­ri­ence the cool­ing ben­e­fits of tree shade, thus ensur­ing that the island becomes a place to escape the city heat in upcom­ing summers. 

Besides shade, what oth­er ben­e­fits do these 3,500 trees pro­vide for New York­ers? For one, trees are experts at remov­ing pol­lu­tion from the air. The Island’s for­est removes 1,160 pounds of air pol­lu­tants annu­al­ly, improv­ing the air qual­i­ty and lung health of peo­ple in the sur­round­ing area. The more trees in a giv­en area, the bet­ter the air qual­i­ty which trans­lates to reduced rates of asth­ma and stress, and improved cog­ni­tion.

Trees also ben­e­fit the health of the plan­et by stor­ing car­bon. The trees of Gov­er­nors Island con­tain approx­i­mate­ly 1,245 tons of stored car­bon, and every year they cap­ture and sequester an addi­tion­al 22 tons. Mature trees store more car­bon that younger ones, sim­ply because they have more sur­face area and larg­er root sys­tems. Every year, trees grow a dense net­work of small feed­er roots, made of car­bon, that will die and be turned into organ­ic mat­ter in the late fall. The larg­er the tree, the more feed­er roots they grow each year, and the more car­bon they sequester underground. 

This is just one rea­son why the Trust is ded­i­cat­ed to main­tain­ing the health and longevi­ty of as many mature trees as pos­si­ble, and is tak­ing steps to reduce the upper canopy of at-risk trees so their roots sys­tems can con­tin­ue to cap­ture and store car­bon for many years to come. 

In addi­tion to stor­ing car­bon, trees can help mit­i­gate the effects of cli­mate change by reduc­ing storm dam­age and runoff. Tree roots act as giant sponges, soak­ing up vast quan­ti­ties of water that could quick­ly turn into tox­ic runoff, and the canopy inter­cepts del­uges of rain that would oth­er­wise hit the ground with force and cause com­paction or flash floods. On Gov­er­nors Island, the canopy pre­vents up to 378,000 gal­lons of runoff annu­al­ly, improv­ing the soil of our park space and pre­vent­ing pol­lu­tants from con­t­a­m­i­nat­ing New York Harbor.

All the data result­ing from this sur­vey is incred­i­bly valu­able to the Trust for Gov­er­nors Island, as it will help inform deci­sions on tree plant­i­ng, park main­te­nance, con­struc­tion projects, and pro­gram­ming events. The 3,500 trees on Gov­er­nors Island are a vital resource to the peo­ple of New York, and the Trust is com­mit­ted to ensur­ing that this cru­cial urban for­est remains healthy and resilient for many years to come. To learn more about urban forests and trees, come to Gov­er­nors Island on Octo­ber 15 for our City of For­est Day event — includ­ing a spe­cial vol­un­teer activ­i­ty and a tree walk­ing tour around the Island. Click here to learn more and register.